code: func (ps *PrintSettings) HasKey(key string) bool {
  	cstr := C.CString(key)
  	defer C.free(unsafe.Pointer(cstr))
  	c := C.gtk_print_settings_has_key(ps.native(), (*C.gchar)(cstr))
  	return gobool(c)
  }
docs: // HasKey() is a wrapper around gtk_print_settings_has_key().