code: def _jws_payload(expire_at, requrl=None, **kwargs):
      
      data = {
          'exp': expire_at,
          'aud': requrl
      }
      data.update(kwargs)
  
      datajson = json.dumps(data, sort_keys=True).encode('utf8')
      return base64url_encode(datajson)
docs: Produce a base64-encoded JWS payload.
  
      expire_at, if specified, must be a number that indicates
      a timestamp after which the message must be rejected.
  
      requrl, if specified, is used as the "audience" according
      to the JWT spec.
  
      Any other parameters are passed as is to the payload.