+ # The origin of the definition.
+ #
+ # Most model entities are defined in a specific place in the source base.
+ #
+ # Because most model entities have one,
+ # it is simpler for the client to have a non-nullable return value.
+ # For entities that lack a location, mock-up special locations are used instead.
+ # By default it is `model.no_location`.
+ fun location: Location do return model.no_location
+