xor gate in voluptuous

voluptuous.xor.py

def xor(fields, group_name):
    """Creates an Exclusive OR (XOR) logical gate voluptuous schema.

    see https://github.com/alecthomas/voluptuous/issues/126

    :param fields: fields comprising the exclusive group.
    :type fields: Dict[str, Schema]
    :param group_name: exclusive group identifier.
    :type group_name: str
    :returns: XOR gated voluptuous schema.
    :rtype: Schema
    """
    return vl.All(
        vl.Any(*(vl.Schema({vl.Required(name): schema}, extra=vl.ALLOW_EXTRA) for name, schema in fields.iteritems())),
        vl.Schema({vl.Exclusive(name, group_name): schema for name, schema in fields.iteritems()}))