developer_notes.md

meta dictionary

Some types have a _meta attribute and a corresponding meta property. It holds a dictionary of key value pairs used to store additional type specific information. Information used at some point are:

• Labels

  • origin
  • params
  • reference

• InputData

  • access_coordinates
  • access_distances
  • access_neighbours

• Bundle

The key and values are not restricted. To save memory if meta information is not used, the _meta attribute may be set to None. The meta property should always return an empty dictionary in this cases. For extension types, _meta should be public typed as dict. The corresponding setter for meta should check the given value to be either None or a MutableMapping.