code: def get_content(self, url):
          
          cache_path = self._url_to_path(url)
          try:
              with open(cache_path, 'rb') as f:
                  return f.read()
          except IOError:
              return None
docs: Returns the content of a cached resource.
  
          Args:
              url: The url of the resource
  
          Returns:
              The content of the cached resource or None if not in the cache