private static boolean isSingleCharacterStringLiteral(PsiExpression arg) {
      final PsiType type = arg.getType();
      if (!TypeUtils.isJavaLangString(type)) {
        return false;
      }
      if (!(arg instanceof PsiLiteralExpression literal)) {
        return false;
      }
      final String value = (String)literal.getValue();
      return value != null && value.length() == 1;
    }
private static boolean isSingleCharacterStringLiteral(PsiExpression arg)