@Contract(pure = true)
  public static boolean equalsIgnoreWhitespaces(@Nullable CharSequence s1, @Nullable CharSequence s2) {
    return Strings.equalsIgnoreWhitespaces(s1, s2);
  }
@Contract(pure = true)
  public static boolean equalsIgnoreWhitespaces(@Nullable CharSequence s1, @Nullable CharSequence s2)