Vendor/phpspreadsheet/phpoffice/phpspreadsheet/src/PhpSpreadsheet/Calculation/Calculation.php
private function strcmpLowercaseFirst($str1, $str2)
    {
        $inversedStr1 = Shared\StringHelper::strCaseReverse($str1);
        $inversedStr2 = Shared\StringHelper::strCaseReverse($str2);

        return strcmp($inversedStr1, $inversedStr2);
    }
private function strcmpLowercaseFirst($str1, $str2)
    {
        $inversedStr1 = Shared\StringHelper::strCaseReverse($str1);
        $inversedStr2 = Shared\StringHelper::strCaseReverse($str2);

        return strcmp($inversedStr1, $inversedStr2);
    }
Compare two strings in the same way as strcmp() except that lowercase come before uppercase letters.

@param string $str1 First string value for the comparison
@param string $str2 Second string value for the comparison

@return int