code: def get_http_body(req, content_type=URL_ENCODED):
      
      if URL_ENCODED in content_type:
          return req.to_urlencoded()
      elif JSON_ENCODED in content_type:
          return req.to_json()
      elif JOSE_ENCODED in content_type:
          return req  # already packaged
      else:
          raise UnSupported(
              "Unsupported content type: '%s'" % content_type)
docs: Get the message into the format that should be places in the body part
      of a HTTP request.
  
      :param req: The service request as a  :py:class:`oidcmsg.message.Message`
          instance
      :param content_type: The format of the body part.
      :return: The correctly formatet service request.