Combines all the given validator callables into one, running all the
    validators in sequence on the given value.

def All(*validators):
    """
    Combines all the given validator callables into one, running all the
    validators in sequence on the given value.
    """
    @wraps(All)
    def built(value):
        for validator in validators:
            value = validator(value)
        return value
    return built