docs: def _to_dict(self):
          """Return a json dictionary representing this model."""
          _dict = {}
          if hasattr(self, 'entity') and self.entity is not None:
              _dict['entity'] = self.entity
          if hasattr(self, 'description') and self.description is not None:
              _dict['description'] = self.description
          if hasattr(self, 'metadata') and self.metadata is not None:
              _dict['metadata'] = self.metadata
          if hasattr(self, 'fuzzy_match') and self.fuzzy_match is not None:
              _dict['fuzzy_match'] = self.fuzzy_match
          if hasattr(self, 'created') and self.created is not None:
              _dict['created'] = datetime_to_string(self.created)
          if hasattr(self, 'updated') and self.updated is not None:
              _dict['updated'] = datetime_to_string(self.updated)
          if hasattr(self, 'values') and self.values is not None:
              _dict['values'] = [x._to_dict() for x in self.values]
          return _dict