fix ISO week calculation

Author: komed3

src/rtbnext/resource/collection.py

@@ -166,7 +166,7 @@ def year( self, year: int ) -> Self:
     def month( self, year: int, month: int ) -> Self:
         """Filters resources by month."""
 
-        prefix = f"{ year }-{ month:02d }-"
+        prefix = f"{ year }-{month:02d}-"
 
         return self._clone( [
             item for item in self._items

src/rtbnext/resource/series.py

@@ -82,11 +82,11 @@ def _period( self, date: str, period: AggregatePeriod ) -> str:
             return f"{ year }-Q{ ( month - 1 ) // 3 + 1 }"
 
         if period == "month":
-            return f"{ year }-{ month:02d }"
+            return f"{ year }-{month:02d}"
 
         if period == "week":
-            current, first = date_type( year, month, day ), date_type( year, 1, 1 )
-            return f"{ year }-W{ ( ( current - first ).days // 7 + 1 ):02d }"
+            iso_year, iso_week, _ = date_type( year, month, day ).isocalendar()
+            return f"{ iso_year }-W{iso_week:02d}"
 
         raise ValueError( f"Invalid aggregate period: { period }" )