def DEFINE_enum(name, default, enum_values, help, flag_values=FLAGS, **args):
 DEFINE_flag(EnumFlag(name, default, help, enum_values, **args), flag_values)

def DEFINE_enum ( name , default , enum_values , help , flag_values = FLAGS , ** args ) : DEFINE_flag ( EnumFlag ( name , default , help , enum_values , ** args ) , flag_values )
registers a flag whose value can be any string from enum_values .