code: def add_user(self, user, **kwargs):
          
          if isinstance(user, User):
              user = user['id']
  
          assert isinstance(user, six.string_types)
  
          endpoint = '{0}/{1}/users/{2}'.format(
              self.endpoint,
              self['id'],
              user,
          )
          result = self.request('PUT', endpoint=endpoint, query_params=kwargs)
          return result
docs: Add a user to this team.