code: func (v *Window) GetApplication() (*Application, error) {
  	c := C.gtk_window_get_application(v.native())
  	if c == nil {
  		return nil, nilPtrErr
  	}
  
  	return wrapApplication(glib.Take(unsafe.Pointer(c))), nil
  }
docs: // GetApplication is a wrapper around gtk_window_get_application().