private function checkForValidPhp($content) : bool
    {
        $len = strlen($content);
        $start = 0;
        $valid = false;
        while (($start = strpos($content, '<?', $start)) !== false) {
            $valid = true;
            $start++;
            $end = strpos($content, '?>', $start + 1);
            if ($end === false) {
                $end = $len;
            }
            while (++$start < $end) {
                $content = ord($content[$start]);
                if ($content < 9 || ($content >= 14 && $content <= 31) || $content == 11 || $content == 12) {
                    return false;
                }
            }
        }

        return $valid;
    }
private function checkForValidPhp($content) : bool
    {
        $len = strlen($content);
        $start = 0;
        $valid = false;
        while (($start = strpos($content, '<?', $start)) !== false) {
            $valid = true;
            $start++;
            $end = strpos($content, '?>', $start + 1);
            if ($end === false) {
                $end = $len;
            }
            while (++$start < $end) {
                $content = ord($content[$start]);
                if ($content < 9 || ($content >= 14 && $content <= 31) || $content == 11 || $content == 12) {
                    return false;
                }
            }
        }

        return $valid;
    }
@param $content

@return bool