code: def to_dict(self):
          
          dict_with_nones = self._asdict()
          codedeploy_lambda_alias_update_dict = dict((k, v) for k, v in dict_with_nones.items()
                                                     if v != ref(None) and v is not None)
          return {'CodeDeployLambdaAliasUpdate': codedeploy_lambda_alias_update_dict}
docs: :return: a dict that can be used as part of a cloudformation template