How to check if the embedded iOS application is uninstalled?

Question

I am trying to detect embedded iOS applications (Calendar, Reminders, Weather) that exist or not.

I tried to use canOpenURL:.

- (BOOL) isCalendarExist {
  UIApplication *app = [UIApplication sharedApplication];  
  NSURL *calUrl= [NSURL URLWithString: @"calshow://"];
  return [app canOpenURL: calUrl];
}

But it canOpenURL:always returns a value TRUE, even if the calendar is deleted.

Is there a way to check if an embedded application exists?