docs: def _to_dict(self):
          """Return a json dictionary representing this model."""
          _dict = {}
          if hasattr(self, 'behavior') and self.behavior is not None:
              _dict['behavior'] = self.behavior
          if hasattr(self, 'dialog_node') and self.dialog_node is not None:
              _dict['dialog_node'] = self.dialog_node
          if hasattr(self, 'selector') and self.selector is not None:
              _dict['selector'] = self.selector
          return _dict