code: private static function checkSheetCodeName($pValue)
      {
          $CharCount = Shared\StringHelper::countCharacters($pValue);
          if ($CharCount == 0) {
              throw new Exception('Sheet code name cannot be empty.');
          }
          // Some of the printable ASCII characters are invalid:  * : / \ ? [ ] and  first and last characters cannot be a "'"
          if ((str_replace(self::$invalidCharacters, '', $pValue) !== $pValue) ||
              (Shared\StringHelper::substring($pValue, -1, 1) == '\'') ||
              (Shared\StringHelper::substring($pValue, 0, 1) == '\'')) {
              throw new Exception('Invalid character found in sheet code name');
          }
  
          // Maximum 31 characters allowed for sheet title
          if ($CharCount > 31) {
              throw new Exception('Maximum 31 characters allowed in sheet code name.');
          }
  
          return $pValue;
      }
docs: Check sheet code name for valid Excel syntax.
  
  @param string $pValue The string to check
  
  @throws Exception
  
  @return string The valid string