code: public static function clean($path, $ds=DIRECTORY_SEPARATOR)
    {
      if ( !is_string($path) && !empty($path) ){
        return '';
        throw new Exception('Path::clean: $path is not a string or is empty.');
      }
      
      $path = trim($path);
      
      if ( empty($path) ){
        $path = self::$ROOT_PATH;
      }
      
      // Remove double slashes and backslashes and convert all slashes and backslashes to DIRECTORY_SEPARATOR
      // If dealing with a UNC path don't forget to prepend the path with a backslash.
      elseif ( $ds == '\\' && $path[0] == '\\' && $path[1] == '\\' ){
        $path = "\\" . preg_replace('#[/\\\\]+#', $ds, $path);
      }
      else {
        $path = preg_replace('#[/\\\\]+#', $ds, $path);
      }
  
      return $path;
    }
docs: Function to strip additional / or \ in a path name.
  
  @param   string  $path  The path to clean.
  @param   string  $ds    Directory separator (optional).
  @return   string  The cleaned path
  @throws   Exception