protected function getPhpFiles($path)
    {
        if (is_dir($path)) {
            return new RegexIterator(
                new RecursiveIteratorIterator(
                    new RecursiveDirectoryIterator($path, RecursiveDirectoryIterator::SKIP_DOTS),
                    RecursiveIteratorIterator::SELF_FIRST,
                    RecursiveIteratorIterator::CATCH_GET_CHILD // Ignore "Permission denied"
                ),
                '/^.+\.php$/i',
                RecursiveRegexIterator::GET_MATCH
            );
        }
        else {
            return [];
        }
    }