docs: def list_models(self, **kwargs):
          """
          List models.
  
          Lists Watson Knowledge Studio [custom
          models](https://cloud.ibm.com/docs/services/natural-language-understanding/customizing.html)
          that are deployed to your Natural Language Understanding service.
  
          :param dict headers: A `dict` containing the request headers
          :return: A `DetailedResponse` containing the result, headers and HTTP status code.
          :rtype: DetailedResponse
          """
  
          headers = {}
          if 'headers' in kwargs:
              headers.update(kwargs.get('headers'))
          sdk_headers = get_sdk_headers('natural-language-understanding', 'V1',
                                        'list_models')
          headers.update(sdk_headers)
  
          params = {'version': self.version}
  
          url = '/v1/models'
          response = self.request(
              method='GET',
              url=url,
              headers=headers,
              params=params,
              accept_json=True)
          return response