code: def _GetUrl(self, url, cache, database):
      
      if not url:
        return ''
  
      url_cache_results = cache.GetResults('url')
      if not url_cache_results:
        result_set = database.Query(self._URL_CACHE_QUERY)
  
        cache.CacheQueryResults(result_set, 'url', 'id', ('url', 'title'))
        url_cache_results = cache.GetResults('url')
  
      reference_url, reference_title = url_cache_results.get(url, ['', ''])
  
      if not reference_url:
        return ''
  
      return '{0:s} ({1:s})'.format(reference_url, reference_title)
docs: Retrieves an URL from a reference to an entry in the from_visit table.
  
      Args:
        url (str): URL.
        cache (SQLiteCache): cache.
        database (SQLiteDatabase): database.
  
      Returns:
        str: URL or an empty string if no URL was found.