docs: def _to_dict(self):
          """Return a json dictionary representing this model."""
          _dict = {}
          if hasattr(self, 'party') and self.party is not None:
              _dict['party'] = self.party
          if hasattr(self, 'importance') and self.importance is not None:
              _dict['importance'] = self.importance
          if hasattr(self, 'role') and self.role is not None:
              _dict['role'] = self.role
          if hasattr(self, 'addresses') and self.addresses is not None:
              _dict['addresses'] = [x._to_dict() for x in self.addresses]
          if hasattr(self, 'contacts') and self.contacts is not None:
              _dict['contacts'] = [x._to_dict() for x in self.contacts]
          return _dict