'Retrieve a value from the cache.
:param key: the value\'s key.
:param \**kw: cache configuration arguments.  The
backend is configured using these arguments upon first request.
Subsequent requests that use the same series of configuration
values will use that same backend.'

def get(self, key, **kw):

    return self.impl.get(key, **self._get_cache_kw(kw, None))
