public static function copy($src, $dst): bool
  {
    if ( is_file($src) ){
      return copy($src, $dst);
    }
    if ( is_dir($src) && self::create_path($dst) ){
      $files = self::get_files($src);
      $dirs = self::get_dirs($src);
      foreach ( $files as $f ){
        copy($f, $dst.'/'.basename($f));
      }
      foreach ( $dirs as $f ){
        self::copy($f, $dst.'/'.basename($f));
      }
      return true;
    }
    else{
      return false;
    }
  }