From acecddae70b9f7e823f50d328439dd9b1c5b83b0 Mon Sep 17 00:00:00 2001
From: Parker Norton <pnorton@usgs.gov>
Date: Mon, 11 May 2026 11:02:56 -0600
Subject: [PATCH 1/7] Remove ParameterSet.py (entirely commented-out dead code)

---
 pyPRMS/parameters/ParameterSet.py | 96 -------------------------------
 1 file changed, 96 deletions(-)
 delete mode 100644 pyPRMS/parameters/ParameterSet.py

diff --git a/pyPRMS/parameters/ParameterSet.py b/pyPRMS/parameters/ParameterSet.py
deleted file mode 100644
index 61e89d1..0000000
--- a/pyPRMS/parameters/ParameterSet.py
+++ /dev/null
@@ -1,96 +0,0 @@
-
-# class ParameterSet(object):
-    # def degenerate_parameters(self):
-    #     """Print parameters that have fewer dimensions than specified in the master parameters."""
-    #
-    #     result = []
-    #     # TODO: 20230726 PAN - This is not needed with the current parameter code
-    #     if self.__master_params is not None:
-    #         for kk, vv in self.parameters.items():
-    #             try:
-    #                 if set(vv.dimensions.keys()) != set(self.__master_params[kk].dimensions.keys()):
-    #                     if not (set(self.__master_params[kk].dimensions.keys()).issubset(set(HRU_DIMS)) and
-    #                             set(vv.dimensions.keys()).issubset(HRU_DIMS)):
-    #                         result.append(kk)
-    #                         if self.verbose:
-    #                             print(f'Parameter, {kk}, is degenerate')
-    #                             print('  parameter: ', list(vv.dimensions.keys()))
-    #                             print('     master: ', list(self.__master_params[kk].dimensions.keys()))
-    #             except ValueError:
-    #                 if self.verbose:
-    #                     print(f'ERROR: Parameter, {kk}, is not a valid PRMS parameter')
-    #     return result
-
-    # def expand_parameter(self, name: str):
-    #     """Expand an existing parameter.
-    #
-    #     Expand (e.g. reshape) a parameter, broadcasting existing value(s) into
-    #     new shape specified by master parameters. The hru_deplcrv parameter has
-    #     special handling to also update the snarea_curve parameter.
-    #
-    #     :param name: name of parameter
-    #     """
-    #     # TODO: 20230726 PAN - This is not needed with the current parameter code
-    #     if self.__master_params is not None:
-    #         # 1) make sure parameter exists
-    #         if self.__master_params.exists(name):
-    #             # 2) get dimensions from master parameters
-    #             new_dims = self.__master_params.parameters[name].dimensions.copy()
-    #
-    #             # The new_dims copy is no longer of type Dimensions, instead it
-    #             # is an OrderedDict
-    #             # 3) get dimension sizes from global dimensions object
-    #             for kk, vv in new_dims.items():
-    #                 vv.size = self.__dimensions[kk].size
-    #
-    #             if self.verbose and set(new_dims.keys()) == set(self.__parameters[name].dimensions.keys()):
-    #                 print(f'Parameter, {name}, already has the maximum number of dimensions')
-    #                 print('    current: ', list(self.__parameters[name].dimensions.keys()))
-    #                 print('  requested: ', list(new_dims.keys()))
-    #
-    #                 # TODO: Write special case where hru_deplcrv is dimensioned nhru, but
-    #                 #       the number of snarea_curve entries is less than nhru * 11.
-    #             else:
-    #                 # 4) call reshape for the parameter
-    #                 self.__parameters[name].reshape(new_dims)
-    #
-    #                 if name == 'hru_deplcrv':
-    #                     # hru_deplcrv needs special handling
-    #                     # 2) get current value of hru_deplcrv, this is the snow_index to use
-    #                     # 3) replace broadcast original value with np.arange(1:nhru)
-    #                     orig_index = self.__parameters[name].data[0] - 1
-    #                     new_indices = np.arange(1, new_dims['nhru'].size + 1)
-    #                     self.__parameters['hru_deplcrv'].data = new_indices
-    #
-    #                     # 5) get snarea_curve associated with original hru_deplcrv value
-    #                     curr_snarea_curve = self.__parameters['snarea_curve'].data.reshape((-1, 11))[orig_index, :]
-    #
-    #                     # 6) replace current snarea_curve values with broadcast of select snarea_curve*nhru
-    #                     new_snarea_curve = np.broadcast_to(curr_snarea_curve, (new_dims['nhru'].size, 11))
-    #                     # 7) reset snarea_curve dimension size to nhru*11
-    #                     self.__parameters['snarea_curve'].dimensions['ndeplval'].size = new_dims['nhru'].size * 11
-    #                     self.__parameters['snarea_curve'].data = new_snarea_curve.flatten(order='C')
-    #
-    #                     if self.verbose:
-    #                         print('hru_deplcrv and snarea_curve have been expanded/updated')
-
-    # def remove_by_global_id(self, hrus: Optional[List] = None,
-    #                         segs: Optional[List] = None):
-    #     """Removes data-by-id (nhm_seg, nhm_id) from all parameters.
-    #
-    #     :param hrus: List of HRU IDs to remove
-    #     :param segs: List of segment IDs to remove
-    #     """
-    #     self.__parameters.remove_by_global_id(hrus=hrus, segs=segs)
-    #
-    #     # Adjust the global dimensions
-    #     if segs is not None:
-    #         self.__dimensions['nsegment'].size -= len(segs)
-    #
-    #     if hrus is not None:
-    #         self.__dimensions['nhru'].size -= len(hrus)
-    #
-    #         if self.__dimensions.exists('nssr'):
-    #             self.__dimensions['nssr'].size -= len(hrus)
-    #         if self.__dimensions.exists('ngw'):
-    #             self.__dimensions['ngw'].size -= len(hrus)

From 0f5511a87b0a825df059a71f3b940a7977573167 Mon Sep 17 00:00:00 2001
From: Parker Norton <pnorton@usgs.gov>
Date: Mon, 11 May 2026 11:09:00 -0600
Subject: [PATCH 2/7] Modernize type hints across parameters directory

- Add 'from __future__ import annotations' to all parameter files
- Replace typing.Dict, List, Set, Optional, Union with built-in
  generics and X | Y syntax
- Simplify super() calls to Python 3 style
- Remove commented-out Rich console setup code
- Fix verbose parameter types: Optional[bool] -> bool (None was never
  a meaningful value)
---
 pyPRMS/parameters/ParamDb.py         |  7 +--
 pyPRMS/parameters/Parameter.py       | 43 +++++++--------
 pyPRMS/parameters/ParameterFile.py   | 21 +++-----
 pyPRMS/parameters/ParameterNetCDF.py |  6 +--
 pyPRMS/parameters/Parameters.py      | 81 ++++++++++++++--------------
 5 files changed, 75 insertions(+), 83 deletions(-)

diff --git a/pyPRMS/parameters/ParamDb.py b/pyPRMS/parameters/ParamDb.py
index 791d42a..76d780a 100644
--- a/pyPRMS/parameters/ParamDb.py
+++ b/pyPRMS/parameters/ParamDb.py
@@ -1,7 +1,8 @@
+from __future__ import annotations
 
 import os
 import pandas as pd     # type: ignore
-from typing import cast, Optional
+from typing import cast
 
 from ..constants import PRMS_VERSION
 from ..Exceptions_custom import ParameterNotValidError
@@ -17,7 +18,7 @@
 class ParamDb(Parameters):
     def __init__(self, paramdb_dir: str,
                  metadata,
-                 verbose: Optional[bool] = False):
+                 verbose: bool = False):
         """Initialize ParamDb object.
 
         This object handles the monolithic parameter database.
@@ -26,7 +27,7 @@ def __init__(self, paramdb_dir: str,
         :param verbose: Output additional debug information
         """
 
-        super(ParamDb, self).__init__(metadata=metadata, verbose=verbose)
+        super().__init__(metadata=metadata, verbose=verbose)
 
         global con
         con = get_console_instance()
diff --git a/pyPRMS/parameters/Parameter.py b/pyPRMS/parameters/Parameter.py
index 2a267cc..592b457 100644
--- a/pyPRMS/parameters/Parameter.py
+++ b/pyPRMS/parameters/Parameter.py
@@ -1,8 +1,10 @@
+from __future__ import annotations
+
 import functools
 import numpy as np
 import numpy.typing as npt
 import pandas as pd     # type: ignore
-from typing import Any, cast, Dict, List, NamedTuple, Optional, Union
+from typing import Any, cast, NamedTuple
 import xml.etree.ElementTree as xmlET
 
 from ..base.console import get_console_instance
@@ -10,15 +12,10 @@
 from ..dimensions.Dimensions import ParamDimensions
 from ..Exceptions_custom import FixedDimensionError
 
-# from rich.console import Console
-# from rich import pretty
-#
-# pretty.install()
-# con = Console(force_jupyter=False)
 con = None
 
-ParamDataRawType = Union[npt.NDArray, np.int32, np.float32, np.float64, np.str_]
-ParamDataType = Union[npt.NDArray, np.int32, np.float32, np.float64, np.str_, int, float, str]
+ParamDataRawType = npt.NDArray | np.int32 | np.float32 | np.float64 | np.str_
+ParamDataType = npt.NDArray | np.int32 | np.float32 | np.float64 | np.str_ | int | float | str
 
 
 class Outliers(NamedTuple):
@@ -29,10 +26,10 @@ class Outliers(NamedTuple):
 
 class Stats(NamedTuple):
     name: str
-    min: Optional[npt.DTypeLike]
-    max: Optional[npt.DTypeLike]
-    mean: Optional[npt.DTypeLike]
-    median: Optional[npt.DTypeLike]
+    min: npt.DTypeLike | None
+    max: npt.DTypeLike | None
+    mean: npt.DTypeLike | None
+    median: npt.DTypeLike | None
 
 
 class Parameter(object):
@@ -44,10 +41,10 @@ class Parameter(object):
 
     # Container for a single parameter
     def __init__(self, name: str,
-                 meta: Optional[Dict] = None,
+                 meta: dict | None = None,
                  global_dims=None,
-                 strict: Optional[bool] = True,
-                 verbose: Optional[bool] = False):
+                 strict: bool = True,
+                 verbose: bool = False):
         """
         Initialize a parameter object.
 
@@ -86,7 +83,7 @@ def __init__(self, name: str,
                 # The meta must be supplied as an adhoc dictionary
                 self.meta = meta
 
-        self.__data: Optional[ParamDataRawType] = None
+        self.__data: ParamDataRawType | None = None
         self.__modified = False
 
     def __str__(self) -> str:
@@ -245,7 +242,7 @@ def dimensions(self) -> ParamDimensions:
         return self.__dimensions
 
     @property
-    def index_map(self) -> Union[Dict[Any, int], None]:
+    def index_map(self) -> dict[Any, int] | None:
         """Returns an ordered dictionary which maps data values of a 1D array
         to index positions.
 
@@ -275,7 +272,7 @@ def modified(self) -> bool:
         return self.__modified
 
     @property
-    def modules(self) -> List[str]:
+    def modules(self) -> list[str]:
         """Returns the names of the PRMS modules that require the parameter.
 
         :returns: names of PRMS modules that require the parameter
@@ -422,7 +419,7 @@ def outliers(self) -> Outliers:
 
         return Outliers(self.__name, values_under, values_over)
 
-    def remove_by_index(self, dim_name: str, indices: List[int]):
+    def remove_by_index(self, dim_name: str, indices: list[int]):
         """Remove columns (nhru or nsegment) from data array given a list of indices.
 
         :param dim_name: Name of dimension to reduce
@@ -522,7 +519,7 @@ def subset_by_index(self, dim_name: str, indices):
         assert self.data_raw is not None  # Needed so mypy doesn't fail on next line
         self.dimensions[dim_name].size = self.data_raw.shape[dim_idx]
 
-    def tolist(self) -> List[Union[int, float, str]]:
+    def tolist(self) -> list[int | float | str]:
         """Returns the parameter data as a list.
 
         :returns: Parameter data
@@ -572,14 +569,14 @@ def tostructure(self) -> dict:
                  'data': self.tolist()}
         return param
 
-    def unique(self) -> Optional[npt.NDArray]:
+    def unique(self) -> npt.NDArray | None:
         """Create array of unique values from the parameter data.
 
         :returns: Array of unique values
         """
         return np.unique(self.data_raw)
 
-    def update_element(self, index: int, value: Union[int, float, List[int], List[float]]):
+    def update_element(self, index: int, value: int | float | list[int] | list[float]):
         """Update single value or row of values (e.g. nhru by nmonths) for a
         given local zero-based index in the parameter data array.
 
@@ -634,7 +631,7 @@ def update_element(self, index: int, value: Union[int, float, List[int], List[fl
                 self.__data[index] = value   # type: ignore
                 self.__modified = True
 
-    def _value_index_1d(self, value: Union[int, float, str]) -> npt.NDArray:
+    def _value_index_1d(self, value: int | float | str) -> npt.NDArray:
         """Given a scalar value return the indices where there is a match.
 
         :param value: The value to find in the parameter data array
diff --git a/pyPRMS/parameters/ParameterFile.py b/pyPRMS/parameters/ParameterFile.py
index 2bba119..bf0aea6 100644
--- a/pyPRMS/parameters/ParameterFile.py
+++ b/pyPRMS/parameters/ParameterFile.py
@@ -1,7 +1,7 @@
 
-# from typing import Any,  Union, Dict, List, OrderedDict as OrderedDictType, Set
+from __future__ import annotations
+
 import numpy as np
-from typing import List, Optional, Set
 
 from ..Exceptions_custom import ParameterExistsError, ParameterNotValidError
 from .Parameters import Parameters
@@ -9,11 +9,6 @@
 from ..prms_helpers import get_file_iter
 from ..base.console import get_console_instance
 
-# from rich.console import Console
-# from rich import pretty
-#
-# pretty.install()
-# con = Console()
 con = None
 
 class ParameterFile(Parameters):
@@ -22,7 +17,7 @@ class ParameterFile(Parameters):
 
     def __init__(self, filename: str,
                  metadata,
-                 verbose: Optional[bool] = False):
+                 verbose: bool = False):
                  # verify: Optional[bool] = True):
         """Create the ParameterFile object.
 
@@ -31,7 +26,7 @@ def __init__(self, filename: str,
         :param verify: whether to load the master parameters (default=True)
         """
 
-        super(ParameterFile, self).__init__(metadata=metadata, verbose=verbose)
+        super().__init__(metadata=metadata, verbose=verbose)
 
         global con
         con = get_console_instance()
@@ -40,7 +35,7 @@ def __init__(self, filename: str,
         # self.__header = None
 
         self.__isloaded = False
-        self.__updated_parameters: Set[str] = set()
+        self.__updated_parameters: set[str] = set()
         self.__verbose = verbose
         self.filename = filename
 
@@ -62,12 +57,12 @@ def filename(self, name: str):
 
         self.__isloaded = False
         self.__filename = name
-        self.__header: List[str] = []  # Initialize the list of file headers
+        self.__header: list[str] = []  # Initialize the list of file headers
 
         self._read()
 
     @property
-    def headers(self) -> List[str]:
+    def headers(self) -> list[str]:
         """Get the headers from the parameter file.
 
         :returns: list of headers from parameter file
@@ -76,7 +71,7 @@ def headers(self) -> List[str]:
         return self.__header
 
     @property
-    def updated_parameters(self) -> Set[str]:
+    def updated_parameters(self) -> set[str]:
         """Get list of parameters that had more than one entry in the parameter file.
 
         :returns: list of parameters
diff --git a/pyPRMS/parameters/ParameterNetCDF.py b/pyPRMS/parameters/ParameterNetCDF.py
index 41202d2..dfb7e5e 100644
--- a/pyPRMS/parameters/ParameterNetCDF.py
+++ b/pyPRMS/parameters/ParameterNetCDF.py
@@ -1,6 +1,6 @@
+from __future__ import annotations
 
 import xarray as xr
-from typing import Optional
 
 from .Parameters import Parameters
 from ..base.console import get_console_instance
@@ -16,7 +16,7 @@ class ParameterNetCDF(Parameters):
     def __init__(self,
                  filename: str,
                  metadata,
-                 verbose: Optional[bool] = False):
+                 verbose: bool = False):
         """Initialize ParamDb object.
 
         :param filename: Path the ParamDb netcdf file
@@ -24,7 +24,7 @@ def __init__(self,
         :param verify: Verify parameters against master list
         """
 
-        super(ParameterNetCDF, self).__init__(metadata=metadata, verbose=verbose)
+        super().__init__(metadata=metadata, verbose=verbose)
 
         global con
         con = get_console_instance()
diff --git a/pyPRMS/parameters/Parameters.py b/pyPRMS/parameters/Parameters.py
index 20a66fb..48b2def 100644
--- a/pyPRMS/parameters/Parameters.py
+++ b/pyPRMS/parameters/Parameters.py
@@ -1,3 +1,4 @@
+from __future__ import annotations
 
 import cartopy.crs as ccrs  # type: ignore
 import gc
@@ -13,11 +14,11 @@
 import xml.etree.ElementTree as xmlET
 
 from collections import defaultdict
-from collections.abc import KeysView
+from collections.abc import KeysView, Sequence
 from functools import cached_property
 from packaging.version import Version
 from pathlib import Path
-from typing import Any, Literal, Optional, Sequence, Union, Dict, List, Set, Tuple
+from typing import Any, Literal, cast
 from cartopy.mpl.gridliner import LONGITUDE_FORMATTER, LATITUDE_FORMATTER  # type: ignore
 
 from ..control.Control import Control
@@ -30,8 +31,6 @@
                          NEW_PTYPE_TO_DTYPE, PRMS_VERSION, PRMS6_DEV_VERSION, PTYPE_TO_PRMS_TYPE, NHM_DATATYPES,
                          PARAMETERS_XML, VAR_DELIM)
 
-# from rich.console import Console
-# from rich import pretty
 from rich.table import Table
 
 import os
@@ -53,7 +52,7 @@ class Parameters(object):
     # Create date: 2017-05-01
 
     def __init__(self, metadata: MetaDataType,
-                 verbose: Optional[bool] = False):
+                 verbose: bool = False):
         """Initialize the Parameters object.
 
         Create an ordered dictionary to contain pyPRMS.Parameter objects
@@ -67,16 +66,16 @@ def __init__(self, metadata: MetaDataType,
         # con.print('Parameters: Console info: {}'.format(con))
 
         self.__dimensions = Dimensions(metadata=metadata, verbose=verbose)
-        self.__parameters: Dict[str, Parameter] = dict()
+        self.__parameters: dict[str, Parameter] = dict()
 
         self.verbose = verbose
-        self.__control: Optional[Control] = None
+        self.__control: Control | None = None
         self.__hru_poly = None
-        self.__hru_shape_key: Optional[str] = None
+        self.__hru_shape_key: str | None = None
         self.__seg_poly = None
-        self.__seg_shape_key: Optional[str] = None
-        self.__seg_to_hru: Dict[int, List[int]] = dict()
-        self.__hru_to_seg: Dict[int, int] = dict()
+        self.__seg_shape_key: str | None = None
+        self.__seg_to_hru: dict[int, list[int]] = dict()
+        self.__hru_to_seg: dict[int, int] = dict()
         self.metadata = metadata['parameters']
         self.prms_version = Version(metadata['info']['version'])
 
@@ -116,7 +115,7 @@ def __str__(self) -> str:
         return outstr
 
     @property
-    def control(self) -> Optional[Control]:
+    def control(self) -> Control | None:
         """Get Control object.
 
         :returns: Control object
@@ -169,7 +168,7 @@ def dimensions(self) -> Dimensions:
         return self.__dimensions
 
     @cached_property
-    def hru_to_seg(self) -> Dict[int, int]:
+    def hru_to_seg(self) -> dict[int, int]:
         """Returns an ordered dictionary mapping NHM HRU IDs to HRU NHM segment IDs.
 
         :returns: dictionary mapping nhm_id to hru_segment_nhm
@@ -194,7 +193,7 @@ def missing_params(self) -> Set:
         return pset.difference(set(self.parameters.keys()))
 
     @property
-    def parameters(self) -> Dict[str, Parameter]:
+    def parameters(self) -> dict[str, Parameter]:
         """Returns an ordered dictionary of parameter objects.
 
         :returns: dictionary of Parameter objects
@@ -203,7 +202,7 @@ def parameters(self) -> Dict[str, Parameter]:
         return self.__parameters
 
     @property
-    def poi_to_seg(self) -> Dict[str, int]:
+    def poi_to_seg(self) -> dict[str, int]:
         """Returns a dictionary mapping poi_id to local poi_seg.
 
         :returns: dictionary mapping poi_id to local poi_seg"""
@@ -213,7 +212,7 @@ def poi_to_seg(self) -> Dict[str, int]:
         return dict(np.rec.fromarrays([gage_ids, gage_segments]).tolist())   # type: ignore
 
     @property
-    def poi_to_seg0(self) -> Dict[str, int]:
+    def poi_to_seg0(self) -> dict[str, int]:
         """Returns a dictionary mapping poi_id to local, zero-based poi_seg.
 
         :returns: dictionary mapping poi_id to local, zero-based poi_seg"""
@@ -222,7 +221,7 @@ def poi_to_seg0(self) -> Dict[str, int]:
         return dict(np.rec.fromarrays([gage_ids, gage_segments]).tolist())   # type: ignore
 
     @cached_property
-    def seg_to_hru(self) -> Dict[int, List[int]]:
+    def seg_to_hru(self) -> dict[int, list[int]]:
         """Returns a dictionary mapping HRU global segment IDs to global HRU IDs.
 
         Segment keys equal to zero are for non-routed HRUs. Segment keys greater than
@@ -369,7 +368,7 @@ def add_missing_parameters(self):
             if self.verbose:   # pragma: no cover
                 con.print(f'[bold]{cparam}[/] [gold3] parameter added with default value[/]')
 
-    def add_poi(self, addl_gages: Dict[str, int]):
+    def add_poi(self, addl_gages: dict[str, int]):
         """Add user-specified points of interest (POIs) to the model.
 
         :param addl_gages: Dictionary of user-specified POIs with POI ID as key and segment index as value
@@ -636,7 +635,7 @@ def get_dataframe(self, name: str) -> pd.DataFrame:
         return param_data
 
     def get_subset(self, name: str,
-                   global_ids: List[int]) -> ParamDataRawType:
+                   global_ids: list[int]) -> ParamDataRawType:
         """Returns a subset for a parameter based on the global_ids (e.g. nhm_id, nhm_seg).
 
         :param name: Name of the parameter
@@ -646,7 +645,7 @@ def get_subset(self, name: str,
 
         param = self.get(name)
         dim_set = set(param.dimensions.keys()).intersection({'nhru', 'nssr', 'ngw', 'nsegment', 'ndeplval'})
-        id_index_map: Union[Dict[Any, int], None] = {}
+        id_index_map: dict[Any, int] | None = {}
         cdim = dim_set.pop()
 
         if cdim in ['nhru', 'nssr', 'ngw', 'ndeplval']:
@@ -696,7 +695,7 @@ def get_subset(self, name: str,
                 return np.take(param.data_raw, nhm_idx0, axis=0)    # axis: 0 rows, 1 columns
                 # return param.data_raw[tuple(nhm_idx0), ]
 
-    def outlier_ids(self, name: str) -> List[int]:
+    def outlier_ids(self, name: str) -> list[int]:
         """Returns list of HRU or segment IDs of invalid parameter values
 
         :param name: Name of the parameter
@@ -781,9 +780,9 @@ def parameters_info(self) -> pd.DataFrame:
         return pd.DataFrame.from_records(out_list, columns=col_names)
 
     def plot(self, name: str,
-             output_dir: Optional[str] = None,
-             limits: Optional[Union[LimitOptions, List[float], Tuple[float, float]]] = 'absolute',
-             mask_defaults: Optional[str] = None,
+             output_dir: str | None = None,
+             limits: LimitOptions | list[float] | tuple[float, float] | None = 'absolute',
+             mask_defaults: str | None = None,
              **kwargs):   # pragma: no cover
         """Plot a parameter.
 
@@ -1024,7 +1023,7 @@ def plot(self, name: str,
             else:
                 print('Non-plottable parameter')
 
-    def poi_upstream_hrus(self, poi: Union[str, List[str], KeysView]) -> Dict[str, List[int]]:
+    def poi_upstream_hrus(self, poi: str | list[str] | KeysView) -> dict[str, list[int]]:
         """Returns a dictionary of POI to upstream global HRU IDs.
 
         :param poi: POI ID or list of POI IDs
@@ -1054,7 +1053,7 @@ def poi_upstream_hrus(self, poi: Union[str, List[str], KeysView]) -> Dict[str, L
 
         return poi_hrus
 
-    def poi_upstream_segments(self, poi: Union[str, List[str], KeysView]) -> Dict[str, List[int]]:
+    def poi_upstream_segments(self, poi: str | list[str] | KeysView) -> dict[str, list[int]]:
         """Returns a dictionary of POI to upstream global segment IDs.
 
         :param poi: POI ID or list of POI IDs
@@ -1083,7 +1082,7 @@ def poi_upstream_segments(self, poi: Union[str, List[str], KeysView]) -> Dict[st
 
         return poi_segs
 
-    def remove(self, name: Union[str, Sequence[str], Set[str]]):
+    def remove(self, name: str | Sequence[str] | set[str]):
         """Delete one or more parameters if they exist.
 
         :param name: parameter or list of parameters to remove
@@ -1099,7 +1098,7 @@ def remove(self, name: Union[str, Sequence[str], Set[str]]):
                 if self.verbose:   # pragma: no cover
                     con.print(f'[bold]{cparam}[/] [gold3]parameter removed[/]')
 
-    def remove_poi(self, poi: Union[str, List[str]]):
+    def remove_poi(self, poi: str | list[str]):
         """Remove POIs by gage_id.
 
         :param poi: POI id to remove
@@ -1142,7 +1141,7 @@ def remove_poi(self, poi: Union[str, List[str]]):
                 self.dimensions.get('npoigages').size -= len(poi_del_indices)
                 self.dimensions.get('nobs').size -= len(poi_del_indices)
 
-    def segment_upstream_hrus(self, segs: Union[int, List[int], KeysView, npt.NDArray]) -> Dict[int, List[int]]:
+    def segment_upstream_hrus(self, segs: int | list[int] | KeysView | npt.NDArray) -> dict[int, list[int]]:
         """Returns a dictionary of segment to upstream global HRU IDs.
 
         :param segs: Global segment ID or list of global segment IDs
@@ -1172,7 +1171,7 @@ def segment_upstream_hrus(self, segs: Union[int, List[int], KeysView, npt.NDArra
 
         return seg_hrus
 
-    def segment_upstream_segments(self, segs: Union[int, List[int], KeysView, npt.NDArray]) -> Dict[int, List[int]]:
+    def segment_upstream_segments(self, segs: int | list[int] | KeysView | npt.NDArray) -> dict[int, list[int]]:
         """Returns a dictionary of global segment IDs to upstream global segment IDs.
 
         :param segs: global segment IDs or list of global segment IDs
@@ -1202,8 +1201,8 @@ def segment_upstream_segments(self, segs: Union[int, List[int], KeysView, npt.ND
         return us_segs
 
     def shapefile_hrus(self, filename: str,
-                       layer_name: Optional[str] = None,
-                       shape_key: Optional[str] = None):   # pragma: no cover
+                       layer_name: str | None = None,
+                       shape_key: str | None = None):   # pragma: no cover
         """Read a shapefile or geodatabase that corresponds to HRUs.
 
         :param filename: name of shapefile or geodatabase
@@ -1222,8 +1221,8 @@ def shapefile_hrus(self, filename: str,
         self.__hru_shape_key = shape_key
 
     def shapefile_segments(self, filename: str,
-                           layer_name: Optional[str] = None,
-                           shape_key: Optional[str] = None):   # pragma: no cover
+                           layer_name: str | None = None,
+                           shape_key: str | None = None):   # pragma: no cover
         """Read a shapefile or geodatabase that corresponds to stream segments.
 
         :param filename: name of shapefile or geodatabase
@@ -1242,7 +1241,7 @@ def shapefile_segments(self, filename: str,
         self.__seg_shape_key = shape_key
 
     def stream_network(self, tosegment: str = 'tosegment_nhm',
-                       seg_id: str = 'nhm_seg') -> Union[nx.DiGraph, None]:
+                       seg_id: str = 'nhm_seg') -> nx.DiGraph | None:
         """Create Directed, Acyclic Graph (DAG) of stream network.
 
         :param tosegment: name of parameter to use for HRU tosegment
@@ -1266,7 +1265,7 @@ def stream_network(self, tosegment: str = 'tosegment_nhm',
 
     def update_element(self, name: str,
                        id1: int,
-                       value: Union[int, float, List[int], List[float]]):
+                       value: int | float | list[int] | list[float]):
         """Update single value or row of values (e.g. nhru by nmonths) for a
         given nhm_id, nhm_seg, or 0 (for scalars).
 
@@ -1334,8 +1333,8 @@ def write_paramdb(self, output_dir: str):
             with open(f'{output_dir}/{xx.name}.csv', 'w') as ff:
                 ff.write(xx.toparamdb())
 
-    def write_parameter_file(self, filename: Union[str, Path],
-                             header: Optional[List[str]] = None):
+    def write_parameter_file(self, filename: str | Path,
+                             header: list[str] | None = None):
         """Write a PRMS parameter file.
 
         :param filename: name of parameter file
@@ -1442,7 +1441,7 @@ def write_parameter_file(self, filename: Union[str, Path],
 
         outfile.close()
 
-    def write_parameter_netcdf(self, filename: Union[str, Path]):
+    def write_parameter_netcdf(self, filename: str | Path):
         """Write parameters to a netcdf format file.
 
         :param filename: full path for output file
@@ -1641,7 +1640,7 @@ def _trim_req_params(self, param_set: Set) -> Set:
         return param_set
 
     def _upstream_hrus(self, streamnet: nx.DiGraph,
-                       dsmost_seg: List[int]) -> List[int]:
+                       dsmost_seg: list[int]) -> list[int]:
         """Get list of HRUs that contribute to the given stream segments.
 
         :param streamnet: Directed, Acyclic Graph (DAG) of stream network
@@ -1673,7 +1672,7 @@ def _upstream_hrus(self, streamnet: nx.DiGraph,
         return final_hru_list
 
     def _upstream_segments(self, streamnet: nx.DiGraph,
-                           dsmost_seg: List[int]) -> List[int]:
+                           dsmost_seg: list[int]) -> list[int]:
         """Get list of segments that contribute to the given stream segments.
 
         :param streamnet: Directed, Acyclic Graph (DAG) of stream network

From ab26b42e1bc14c71977492c42ba37d0c24d4bb70 Mon Sep 17 00:00:00 2001
From: Parker Norton <pnorton@usgs.gov>
Date: Mon, 11 May 2026 11:12:01 -0600
Subject: [PATCH 3/7] Replace __getattr__ with explicit collection interface in
 Parameters

- Remove __getattr__ delegation to internal __parameters dict
- Add __contains__ for 'name in params' syntax
- Add __iter__ for 'for name in params:' iteration
- Add __len__ for len(params)
- Update exists() to use __contains__
- Improves IDE support, prevents accidental dict mutation, and
  produces clear error messages on typos
---
 pyPRMS/parameters/Parameters.py | 36 ++++++++++++++++++++++-----------
 1 file changed, 24 insertions(+), 12 deletions(-)

diff --git a/pyPRMS/parameters/Parameters.py b/pyPRMS/parameters/Parameters.py
index 48b2def..15da1ba 100644
--- a/pyPRMS/parameters/Parameters.py
+++ b/pyPRMS/parameters/Parameters.py
@@ -79,25 +79,37 @@ def __init__(self, metadata: MetaDataType,
         self.metadata = metadata['parameters']
         self.prms_version = Version(metadata['info']['version'])
 
-    def __getattr__(self, name: str):
-        """Not sure what to write yet.
+    def __contains__(self, name: str) -> bool:
+        """Check if a parameter exists.
 
-        :param name: Name of the attribute
+        :param name: Name of the parameter
+        :returns: True if parameter exists, otherwise False
         """
-
-        # Undefined attributes will look up the given parameter
-        # return self.get(item)
-        # https://nedbatchelder.com/blog/201010/surprising_getattr_recursion.html
-        if name == "__setstate__":
-            raise AttributeError(name)
-        return getattr(self.__parameters, name)
+        return name in self.__parameters
 
     def __getitem__(self, item):
-        """Not sure what to write yet.
+        """Get a parameter by name.
+
+        :param item: Name of the parameter
+        :returns: Parameter object
         """
 
         return self.get(item)
 
+    def __iter__(self):
+        """Iterate over parameter names.
+
+        :returns: Iterator over parameter names
+        """
+        return iter(self.__parameters)
+
+    def __len__(self) -> int:
+        """Return number of parameters.
+
+        :returns: Number of parameters
+        """
+        return len(self.__parameters)
+
     def __str__(self) -> str:
         """Pretty-print string representation of the Parameters object.
 
@@ -571,7 +583,7 @@ def exists(self, name: str) -> bool:
         :returns: True if parameter exists, otherwise False
         """
 
-        return name in self.parameters.keys()
+        return name in self
 
     def get(self, name: str) -> Parameter:
         """Returns a parameter object.

From 418c29f9e2c0a19650c311fb71af983ec4549315 Mon Sep 17 00:00:00 2001
From: Parker Norton <pnorton@usgs.gov>
Date: Mon, 11 May 2026 11:57:09 -0600
Subject: [PATCH 4/7] Rename __parameters_to_dict to _parameters_to_dict in
 MetaData

- Change from double-underscore (name-mangled private) to single-underscore
  (internal but accessible) since ParamDb already accesses it externally
- Eliminates fragile name-mangled access pattern
  (mobj._MetaData__parameters_to_dict) in ParamDb.py
- Method is now accessed as mobj._parameters_to_dict
---
 pyPRMS/metadata/metadata.py  | 8 ++++----
 pyPRMS/parameters/ParamDb.py | 6 +++---
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/pyPRMS/metadata/metadata.py b/pyPRMS/metadata/metadata.py
index a0fb444..e095115 100644
--- a/pyPRMS/metadata/metadata.py
+++ b/pyPRMS/metadata/metadata.py
@@ -43,7 +43,7 @@ def __init__(self, version: str | Version = PRMS_VERSION,
 
         fcn_map = {'control': self.__control_to_dict,
                    'dimensions': self.__dimensions_to_dict,
-                   'parameters': self.__parameters_to_dict,
+                   'parameters': self._parameters_to_dict,
                    'variables': self.__variables_to_dict,
                    'data_file': self.__data_file_to_dict,
                    'cbh': self.__cbh_to_dict}
@@ -250,9 +250,9 @@ def __control_to_dict(self, xml_root: xmlET.Element,
 
         return meta_dict
 
-    def __parameters_to_dict(self, xml_root: xmlET.Element,
-                             meta_type: str,
-                             req_version: Version) -> dict:
+    def _parameters_to_dict(self, xml_root: xmlET.Element,
+                            meta_type: str,
+                            req_version: Version) -> dict:
         """Convert parameter metadata to dictionary.
 
         :param xml_root: XML root element
diff --git a/pyPRMS/parameters/ParamDb.py b/pyPRMS/parameters/ParamDb.py
index 76d780a..a9c3b53 100644
--- a/pyPRMS/parameters/ParamDb.py
+++ b/pyPRMS/parameters/ParamDb.py
@@ -60,9 +60,9 @@ def _read(self):
 
         # Create a MetaData object to use its parameter parsing function
         mobj = MetaData()
-        pvt_meta = mobj._MetaData__parameters_to_dict(xml_root=params_root,
-                                                      meta_type='parameters',
-                                                      req_version=PRMS_VERSION)
+        pvt_meta = mobj._parameters_to_dict(xml_root=params_root,
+                                             meta_type='parameters',
+                                             req_version=PRMS_VERSION)
 
         # Populate parameterSet with all available parameter names
         for param in params_root.findall('parameter'):

From 003368777d704bdf132e1410026baa027245170e Mon Sep 17 00:00:00 2001
From: Parker Norton <pnorton@usgs.gov>
Date: Mon, 11 May 2026 12:05:55 -0600
Subject: [PATCH 5/7] Remove commented-out dead code from parameter files

- Parameter.py: remove commented-out reshape method (~45 lines),
  size property, old namedtuple comments
- Parameters.py: remove commented-out debug prints, old return
  statements, and alternative implementations
- ParameterFile.py: remove commented-out verify parameter, old
  attribute initializations, and debug print
---
 pyPRMS/parameters/Parameter.py     | 59 ------------------------------
 pyPRMS/parameters/ParameterFile.py |  6 ---
 pyPRMS/parameters/Parameters.py    | 15 --------
 3 files changed, 80 deletions(-)

diff --git a/pyPRMS/parameters/Parameter.py b/pyPRMS/parameters/Parameter.py
index 592b457..9648469 100644
--- a/pyPRMS/parameters/Parameter.py
+++ b/pyPRMS/parameters/Parameter.py
@@ -298,16 +298,6 @@ def ndim(self) -> int:
         else:
             return self.__dimensions.ndim
 
-    # @property
-    # def size(self) -> int:
-    #     """Return the total size of the parameter for the defined dimensions.
-    #
-    #     :returns total size of parameter dimensions"""
-    #     arr_shp = [dd.size for dd in self.dimensions.dimensions.values()]
-    #
-    #     # Compute the total size of the parameter
-    #     return functools.reduce(lambda x, y: x * y, arr_shp)
-
     @property
     def xml(self) -> xmlET.Element:
         """Return the xml metadata for the parameter as an xml Element.
@@ -352,7 +342,6 @@ def check_values(self) -> bool:
 
         :returns: true when all values are within the valid min/max range for the parameter
         """
-        # if self.__data is not None:
         minval = self.meta.get('minimum', None)
         maxval = self.meta.get('maximum', None)
 
@@ -406,7 +395,6 @@ def outliers(self) -> Outliers:
 
         :returns: NamedTuple containing count of values less than and values greater than valid range
         """
-        # Outliers = namedtuple('Outliers', ['name', 'under', 'over'])
 
         values_under = 0
         values_over = 0
@@ -438,58 +426,11 @@ def remove_by_index(self, dim_name: str, indices: list[int]):
         else:
             raise TypeError('Parameter data is not initialized')
 
-    # def reshape(self, new_dims: Dict):
-    #     """Reshape a parameter, broadcasting existing values as necessary.
-    #
-    #     :param new_dims: Dimension names and sizes that will be used to reshape the parameter data
-    #     """
-    #
-    #     if self.__data is None:
-    #         # Reshape has no meaning if there is no data to reshape
-    #         return
-    #
-    #     if self.dimensions.ndim == 1:
-    #         if 'one' in self.dimensions.keys():
-    #             # Reshaping from a scalar to a 1D or 2D array
-    #             # print('Scalar to 1D or 2D')
-    #             new_sizes = [vv.size for vv in new_dims.values()]
-    #             tmp_data = np.broadcast_to(self.__data, new_sizes)
-    #
-    #             # Remove the original dimension
-    #             self.dimensions.remove('one')
-    #
-    #             # Add the new ones
-    #             for kk, vv in new_dims.items():
-    #                 self.dimensions.add(kk, vv.size)
-    #
-    #             self.__data = tmp_data
-    #         elif set(self.dimensions.keys()).issubset(set(new_dims.keys())):
-    #             # Reschaping a 1D to a 2D
-    #             if len(new_dims) == 1:
-    #                 print('ERROR: Cannot reshape from 1D array to 1D array')
-    #             else:
-    #                 # print('1D array to 2D array')
-    #                 new_sizes = [vv.size for vv in new_dims.values()]
-    #                 try:
-    #                     tmp_data = np.broadcast_to(self.__data, new_sizes)
-    #                 except ValueError:
-    #                     # operands could not be broadcast together with remapped shapes
-    #                     tmp_data = np.broadcast_to(self.__data, new_sizes[::-1]).T
-    #
-    #                 old_dim = list(self.dimensions.keys())[0]
-    #                 self.dimensions.remove(old_dim)
-    #
-    #                 for kk, vv in new_dims.items():
-    #                     self.dimensions.add(kk, vv.size)
-    #
-    #                 self.__data = tmp_data
-
     def stats(self) -> Stats:
         """Returns basic statistics on parameter values.
 
         :returns: None (for strings or no data) or NamedTuple containing min, max, mean, and median of parameter values
         """
-        # Stats = namedtuple('Stats', ['name', 'min', 'max', 'mean', 'median'])
 
         try:
             return Stats(self.__name, np.min(self.data_raw), np.max(self.data_raw),
diff --git a/pyPRMS/parameters/ParameterFile.py b/pyPRMS/parameters/ParameterFile.py
index bf0aea6..b0a67bb 100644
--- a/pyPRMS/parameters/ParameterFile.py
+++ b/pyPRMS/parameters/ParameterFile.py
@@ -18,7 +18,6 @@ class ParameterFile(Parameters):
     def __init__(self, filename: str,
                  metadata,
                  verbose: bool = False):
-                 # verify: Optional[bool] = True):
         """Create the ParameterFile object.
 
         :param filename: name of parameter file
@@ -31,9 +30,6 @@ def __init__(self, filename: str,
         global con
         con = get_console_instance()
 
-        # self.__filename = None
-        # self.__header = None
-
         self.__isloaded = False
         self.__updated_parameters: set[str] = set()
         self.__verbose = verbose
@@ -116,8 +112,6 @@ def _read(self):
             if line == VAR_DELIM:
                 continue
             varname = line.split(' ')[0]
-            # if self.__verbose:   # pragma: no cover
-            #     print(f'{varname=}')
 
             # Add the parameter
             try:
diff --git a/pyPRMS/parameters/Parameters.py b/pyPRMS/parameters/Parameters.py
index 15da1ba..dcdad51 100644
--- a/pyPRMS/parameters/Parameters.py
+++ b/pyPRMS/parameters/Parameters.py
@@ -440,7 +440,6 @@ def adjust_bounded_parameters(self):
             cmeta = cparam.meta
 
             if cmeta.get('maximum') in list(self.dimensions.keys()):
-                # if isinstance(cmeta.get('maximum'), str):
                 try:
                     cmeta['maximum'] = self.dimensions.get(cmeta.get('maximum')).size
 
@@ -484,7 +483,6 @@ def check(self):   # pragma: no cover
         """Check all parameter variables for proper array size.
         """
 
-        # for pp in self.__parameters.values():
         for pk in sorted(list(self.parameters.keys())):
             pp = self.get(pk)
 
@@ -505,8 +503,6 @@ def check(self):   # pragma: no cover
                     con.print(f'    [dark_orange]WARNING[/]: Value(s) (range: {pp_stats.min}, {pp_stats.max}) outside '
                               + f'the valid range of ({valid_min}, {valid_max}); '
                               + f'under/over=({pp_outliers.under}, {pp_outliers.over})')
-                    # print(f'    WARNING: Value(s) (range: {pp.data.min()}, {pp.data.max()}) outside ' +
-                    #       f'the valid range of ({pp.minimum}, {pp.maximum})')
                 elif valid_min == 'bounded':
                     # TODO: Handling bounded parameters needs improvement
                     con.print(f'    [dark_orange]WARNING[/]: Bounded parameter value(s) '
@@ -592,7 +588,6 @@ def get(self, name: str) -> Parameter:
         :returns: Parameter object
         """
 
-        # Return the given parameter
         if self.exists(name):
             return self.__parameters[name]
 
@@ -673,7 +668,6 @@ def get_subset(self, name: str,
 
         if param.dimensions.ndim == 2:
             return np.take(param.data_raw, nhm_idx0, axis=0)    # axis: 0 rows, 1 columns
-            # return param.data_raw[tuple(nhm_idx0), :]
         else:
             if name in ['hru_deplcrv', 'snarea_curve']:
                 init_data = np.take(self.get('hru_deplcrv').data_raw, nhm_idx0, axis=0)
@@ -687,7 +681,6 @@ def get_subset(self, name: str,
 
                         # Create new hru_deplcrv and renumber
                         res = np.array([uniq_dict[xx] for xx in init_data])
-                        # return np.array([uniq_dict[xx] for xx in init_data])
                     case 'snarea_curve':
                         uniq_deplcrv0 = [xx - 1 for xx in uniq_deplcrv]
                         res = param.data_raw.reshape((-1, 11))[tuple(uniq_deplcrv0), :].reshape((-1))
@@ -705,7 +698,6 @@ def get_subset(self, name: str,
             else:
                 # All other 1D arrays
                 return np.take(param.data_raw, nhm_idx0, axis=0)    # axis: 0 rows, 1 columns
-                # return param.data_raw[tuple(nhm_idx0), ]
 
     def outlier_ids(self, name: str) -> list[int]:
         """Returns list of HRU or segment IDs of invalid parameter values
@@ -870,7 +862,6 @@ def plot(self, name: str,
                     # Takes care of multipolygons that are in the NHM geodatabase/shapefile
                     geoms_exploded = self.__hru_poly.explode(index_parts=True).reset_index(level=1, drop=True)
 
-                    # print('Writing first plot')
                     df_mrg = geoms_exploded.merge(param_data, left_on=self.__hru_shape_key,
                                                   right_index=True, how='left')
 
@@ -945,7 +936,6 @@ def plot(self, name: str,
 
                             for tt in range(1, 12):
                                 # Months 2 through 12
-                                # print(f'    Index: {tt}')
                                 param_data = self.get_dataframe(name).iloc[:, tt].to_frame(name=name)
 
                                 if mask_defaults is not None:
@@ -1134,9 +1124,6 @@ def remove_poi(self, poi: str | list[str]):
 
         poi_parameters = ['poi_gage_id', 'poi_gage_segment', 'poi_type']
 
-        # print(f'POIs to delete: {poi}')
-        # print(f'Current POIs: {poi_ids}')
-        # print(f'Size of poi_del_indices: {poi_del_indices.size}')
         if len(poi_del_indices) > 0:
             if self.get('poi_gage_id').dimensions.get('npoigages').size == len(poi_del_indices):
                 # We're trying to remove all the POIs
@@ -1505,9 +1492,7 @@ def write_parameter_netcdf(self, filename: str | Path):
             else:
                 # String parameter
                 # Get the maximum string length in the array of data
-                # print('String parameter: {}'.format(vv.name))
                 str_size = len(max(vv.data, key=len))
-                # print('size: {}'.format(str_size))
 
                 # Create a dimension for the string length
                 nc_hdl.createDimension(vv.name + '_nchars', str_size)

From 1819096286a9aa7666323a53ea09e7e5486e60ba Mon Sep 17 00:00:00 2001
From: Parker Norton <pnorton@usgs.gov>
Date: Mon, 11 May 2026 12:14:03 -0600
Subject: [PATCH 6/7] Minor improvements to Parameter.py

- Add __repr__ method for debugging
- Add -> bool return type annotation to is_scalar property
- Replace isinstance(indices, type(dict().values())) with
  isinstance(indices, ValuesView) from collections.abc
---
 pyPRMS/parameters/Parameter.py | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/pyPRMS/parameters/Parameter.py b/pyPRMS/parameters/Parameter.py
index 9648469..7c96bb0 100644
--- a/pyPRMS/parameters/Parameter.py
+++ b/pyPRMS/parameters/Parameter.py
@@ -4,6 +4,7 @@
 import numpy as np
 import numpy.typing as npt
 import pandas as pd     # type: ignore
+from collections.abc import ValuesView
 from typing import Any, cast, NamedTuple
 import xml.etree.ElementTree as xmlET
 
@@ -86,6 +87,13 @@ def __init__(self, name: str,
         self.__data: ParamDataRawType | None = None
         self.__modified = False
 
+    def __repr__(self) -> str:
+        """String representation of the Parameter object.
+
+        :return: string with parameter name and dimensions
+        """
+        return f"Parameter(name='{self.name}')"
+
     def __str__(self) -> str:
         """Pretty-print string representation of the parameter information.
 
@@ -257,7 +265,7 @@ def index_map(self) -> dict[Any, int] | None:
             return None
 
     @property
-    def is_scalar(self):
+    def is_scalar(self) -> bool:
         try:
             return 'one' in self.meta['dimensions']
         except KeyError:
@@ -413,7 +421,7 @@ def remove_by_index(self, dim_name: str, indices: list[int]):
         :param dim_name: Name of dimension to reduce
         :param indices: List of indices to remove"""
 
-        if isinstance(indices, type(dict().values())):
+        if isinstance(indices, ValuesView):
             indices = list(indices)
 
         if self.__data is not None:
@@ -445,7 +453,7 @@ def subset_by_index(self, dim_name: str, indices):
         :param dim_name: name of dimension
         :param indices: local indices of HRUs or segments to extract"""
 
-        if isinstance(indices, type(dict().values())):
+        if isinstance(indices, ValuesView):
             indices = list(indices)
 
         if self.dimensions[dim_name].is_fixed:

From 2e6c91ca5971cec17753e7ab13d57f323e465d20 Mon Sep 17 00:00:00 2001
From: Parker Norton <pnorton@usgs.gov>
Date: Mon, 11 May 2026 12:17:21 -0600
Subject: [PATCH 7/7] Protect parameters property with MappingProxyType

- Return a read-only MappingProxyType view from the parameters property
  instead of the raw internal dict
- Prevents external code from bypassing add()/remove() by directly
  mutating the dict
- All read operations (keys, values, items, [], in, iteration) continue
  to work unchanged
---
 pyPRMS/parameters/Parameters.py | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/pyPRMS/parameters/Parameters.py b/pyPRMS/parameters/Parameters.py
index dcdad51..f9859b2 100644
--- a/pyPRMS/parameters/Parameters.py
+++ b/pyPRMS/parameters/Parameters.py
@@ -18,6 +18,7 @@
 from functools import cached_property
 from packaging.version import Version
 from pathlib import Path
+from types import MappingProxyType
 from typing import Any, Literal, cast
 from cartopy.mpl.gridliner import LONGITUDE_FORMATTER, LATITUDE_FORMATTER  # type: ignore
 
@@ -205,13 +206,13 @@ def missing_params(self) -> Set:
         return pset.difference(set(self.parameters.keys()))
 
     @property
-    def parameters(self) -> dict[str, Parameter]:
-        """Returns an ordered dictionary of parameter objects.
+    def parameters(self) -> MappingProxyType[str, Parameter]:
+        """Returns a read-only view of parameter objects.
 
-        :returns: dictionary of Parameter objects
+        :returns: Read-only mapping of parameter names to Parameter objects
         """
 
-        return self.__parameters
+        return MappingProxyType(self.__parameters)
 
     @property
     def poi_to_seg(self) -> dict[str, int]: