code: def add_team_membership(self, auth, team_id, username):
          
          url = "/admin/teams/{t}/members/{u}".format(t=team_id, u=username)
          self.put(url, auth=auth)
docs: Add user to team.
  
          :param auth.Authentication auth: authentication object, must be admin-level
          :param str team_id: Team's id
          :param str username: Username of the user to be added to team
          :raises NetworkFailure: if there is an error communicating with the server
          :raises ApiFailure: if the request cannot be serviced