toPTRoute method
Convert to a PTRoute from this one.
Returns
- PTRoute object if the route is a public transport route, null otherwise
Implementation
PTRoute? toPTRoute() {
  final OperationResult resultString = objectMethod(
    super.pointerId,
    'Route',
    'toPTRoute',
  );
  if (resultString['result'] == -1) {
    return null;
  }
  return PTRoute.init(resultString['result']);
}