public static function path(string $path = null): ? string
    {
        return $path && $path[0] !== static::DIRECTORY_SEPARATOR
            ? static::DIRECTORY_SEPARATOR . $path
            : $path;
    }
public static function path(string $path = null): ? string
    {
        return $path && $path[0] !== static::DIRECTORY_SEPARATOR
            ? static::DIRECTORY_SEPARATOR . $path
            : $path;
    }
public static function path ( string $ path = null ) : ? string { return $ path && $ path [ 0 ] !== static :: DIRECTORY_SEPARATOR ? static :: DIRECTORY_SEPARATOR . $ path : $ path ; }
Construct a path with the directory separator prepended.

@param string $path The path

@return string
Construct a path with the directory separator prepended .