'Just aggregates the validator methods into a defaultdict
and stores them on cls._validators.'

def __new__(meta, name, bases, attrs):

    validators = collections.defaultdict(set)
    for attr in attrs.values():
        if hasattr(attr, 'validates'):
            validators[attr.validates].add(attr)
    attrs['_validators'] = validators
    cls = type.__new__(meta, name, bases, attrs)
    return cls
