@Override
  public String fromString(@Nullable @NonNls String s, final @NotNull ConvertContext context) {
    if (s == null) return null;

    if (myAllowEmpty && s.trim().length() == 0) return s;

    if (s.trim().length() == 1) return s;

    if (isUnicodeCharacterSequence(s)) {
      try {
        Integer.parseInt(s.substring(UNICODE_PREFIX.length()), 16);
        return s;
      }  catch (NumberFormatException e) {}

    }
    return null;
  }
@Override
  public String fromString(@Nullable @NonNls String s, final @NotNull ConvertContext context)