code: def put_file(self, key, file):
          
          try:
              return self._dstore.put_file(key, file)
          finally:
              self.cache.delete(key)
docs: Implementation of :meth:`~simplekv.KeyValueStore.put_file`.
  
          Will store the value in the backing store. After a successful or
          unsuccessful store, the cache will be invalidated by deleting the key
          from it.