'Creates a group.
:param ctxt: the context of the caller.
:param group: the Group object of the group to be created.
:returns: model_update'

def create_group(self, ctxt, group):

    if volume_utils.is_group_a_cg_snapshot_type(group):
        return self.create_consistencygroup(ctxt, group)
    raise NotImplementedError()
