code: def thumbnail(self, dump_to=None):
          
          headers = {
              "Authorization": "token {}".format(self._client.token)
          }
  
          result = requests.get('{}/{}/thumbnail'.format(self._client.base_url,
                  OAuthClient.api_endpoint.format(id=self.id)),
                  headers=headers)
  
          if not result.status_code == 200:
              raise ApiError('No thumbnail found for OAuthClient {}'.format(self.id))
  
          if dump_to:
              with open(dump_to, 'wb+') as f:
                  f.write(result.content)
          return result.content
docs: This returns binary data that represents a 128x128 image.
          If dump_to is given, attempts to write the image to a file
          at the given location.