docs: def get(self, url, expiration):
          """
          Fetch the feed if no cache exist or if cache is stale
          """
          # Hash url to have a shorter key and add it expiration time to avoid clash for 
          # other url usage with different expiration
          cache_key = self.cache_key.format(**{
              'id': self._hash_url(url),
              'expire': str(expiration)
          })
          
          # Get feed from cache if any
          feed = cache.get(cache_key)
          # Else fetch it
          if feed is None:
              #print "No feed cache, have to fetch it"
              feed = self.fetch(url)
              cache.set(cache_key, feed, expiration)
              
          return self.parse(feed)