def has_flag(conf, atom, flag):
    if flag in get_flags_from_package_conf(conf, atom):
        return True
    return False
Create a L{Field} that can only have a single value.
dataset/ETHPy150Open saltstack/salt/salt/modules/portage_config.py/has_flag--crossover with--dataset/ETHPy150Open ClusterHQ/eliot/eliot/_validation.py/Field.forValue