code: def call(self, default_response=None, **query_params):
          
          query_url = self.get_query_url(**query_params)
          return self._perform_call(query_url, default_response)
docs: Perform a query to the Piwik server and return the response.
  
          :param default_response: Return value in case the query fails
          :param query_params: Dictionary with the parameters of the query