code: def torrent_from_url(self, url, cache=True, prefetch=False):
          
          if self._use_cache(cache) and url in self._torrent_cache:
              return self._torrent_cache[url]
          torrent = Torrent(url, cache, prefetch)
          if cache:
              self._torrent_cache[url] = torrent
          return torrent
docs: Create a Torrent object from a given URL.
  
          If the cache option is set, check to see if we already have a Torrent
          object representing it. If prefetch is set, automatically query the
          torrent's info page to fill in the torrent object. (If prefetch is
          false, then the torrent page will be queried lazily on-demand.)