code: def userstream_user(self, delegate, stall_warnings=None,
                          with_='followings', replies=None):
          
          params = {'stringify_friend_ids': 'true'}
          set_bool_param(params, 'stall_warnings', stall_warnings)
          set_str_param(params, 'with', with_)
          set_str_param(params, 'replies', replies)
  
          svc = TwitterStreamService(
              lambda: self._get_userstream('user.json', params),
              delegate)
          return svc
docs: Streams messages for a single user.
  
          https://dev.twitter.com/docs/api/1.1/get/user
  
          The ``stringify_friend_ids`` parameter is always set to ``'true'`` for
          consistency with the use of string identifiers elsewhere.
  
          :param delegate:
              A delegate function that will be called for each message in the
              stream and will be passed the message dict as the only parameter.
              The message dicts passed to this function may represent any message
              type and the delegate is responsible for any dispatch that may be
              required. (:mod:`txtwitter.messagetools` may be helpful here.)
  
          :param bool stall_warnings:
              Specifies whether stall warnings should be delivered.
  
          :param str with_:
              If ``'followings'`` (the default), the stream will include messages
              from both the authenticated user and the authenticated user's
              followers. If ``'user'``, the stream will only include messages
              from (or mentioning) the autheticated user. All other values are
              invalid. (The underscore appended to the parameter name is to avoid
              conflicting with Python's ``with`` keyword.)
  
          :param str replies:
              If set to ``'all'``, replies to tweets will be included even if the
              authenticated user does not follow both parties.
  
          :returns: An unstarted :class:`TwitterStreamService`.