code: def invite(self, username):
          
          url = self._build_url('memberships', username, base_url=self._api)
          return self._json(self._put(url), 200)
docs: Invite the user to join this team.
  
          This returns a dictionary like so::
  
              {'state': 'pending', 'url': 'https://api.github.com/teams/...'}
  
          :param str username: (required), user to invite to join this team.
          :returns: dictionary