code: def populate_request_data(self, request_args):
          
          request_args['auth'] = HTTPBasicAuth(
              self._username, self._password)
          return request_args
docs: Add the authentication info to the supplied dictionary.
  
          We use the `requests.HTTPBasicAuth` class as the `auth` param.
  
          Args:
              `request_args`: The arguments that will be passed to the request.
          Returns:
              The updated arguments for the request.