'Update/Create a BDM at top level cell.'

def bdm_update_or_create_at_top(self, ctxt, bdm, create=None):

    message = _BroadcastMessage(self, ctxt, 'bdm_update_or_create_at_top', dict(bdm=bdm, create=create), 'up', run_locally=False)
    message.process()
