@Contract(value = "false, _ -> true", pure = true)
  private static boolean pageIsGoodForAnyLanguage(boolean filterOutRainbowNonConflictingAttrKeys,
                                                  @NotNull ColorSettingsPage page) {
    return !filterOutRainbowNonConflictingAttrKeys
           || page instanceof GeneralColorsPage
           || page instanceof RainbowColorSettingsPage;
  }
@Contract(value = "false, _ -> true", pure = true)
  private static boolean pageIsGoodForAnyLanguage(boolean filterOutRainbowNonConflictingAttrKeys,
                                                  @NotNull ColorSettingsPage page)