def Opt(re):
	result = Alt(re, Empty)
	result.str = "Opt(%s)" % re
	return result
Invoked when registering a model with a backend. This is a chance to
dataset/ETHPy150Open probcomp/bayeslite/external/plex/dist/Plex/Regexps.py/Opt--crossover with--dataset/ETHPy150Open lsbardel/python-stdnet/stdnet/backends/__init__.py/BackendDataServer.setup_model