Vendor/phpspreadsheet/phpoffice/phpspreadsheet/src/PhpSpreadsheet/Worksheet/Worksheet.php
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 $pValue;
    }
private static function checkSheetCodeName($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;
    }
Check sheet code name for valid Excel syntax.

@param string $pValue The string to check

@throws Exception

@return string The valid string