'Update an endpoint group.
:param endpoint_group_id: identity of endpoint group to retrieve
:type endpoint_group_id: string
:param endpoint_group: A full or partial endpoint_group
:type endpoint_group: dictionary
:raises keystone.exception.NotFound: If the endpoint group was not
found.
:returns: an endpoint group representation.'

@abc.abstractmethod
def update_endpoint_group(self, endpoint_group_id, endpoint_group):

    raise exception.NotImplemented()
