@classmethod
def with_validators(cls, validators):
    assert all(((vld in VALIDATORS) for vld in validators)), ('allowed validators are ' + ', '.join(VALIDATORS))
    return type(cls.__name__, (cls,), {'validators': validators})
@classmethod
def with_validators(cls, validators):
    assert all(((vld in VALIDATORS) for vld in validators)), ('allowed validators are ' + ', '.join(VALIDATORS))
    return type(cls.__name__, (cls,), {'validators': validators})