class CIDR { CIDR({this.ip = '', this.bits = 0}); String ip; int bits; @override String toString() { return '$ip/$bits'; } String toJson() { return toString(); } factory CIDR.fromString(String val) { final parts = val.split('/'); if (parts.length != 2) { throw 'Invalid CIDR string'; } return CIDR( ip: parts[0], bits: int.parse(parts[1]), ); } }