'Update federated user\'s display name if changed.
:param idp_id: The identity provider ID
:param protocol_id: The federation protocol ID
:param unique_id: The unique ID for the user
:param display_name: The user\'s display name'

@abc.abstractmethod
def update_federated_user_display_name(self, idp_id, protocol_id, unique_id, display_name):

    raise exception.NotImplemented()
