Store a Mor object in the cache with the given name.
        If the key is not in the cache, raises a KeyError.

def set_mor(self, key, name, mor):
        """
        Store a Mor object in the cache with the given name.
        If the key is not in the cache, raises a KeyError.
        """
        with self._mor_lock:
            self._mor[key][name] = mor
            self._mor[key][name]['creation_time'] = time.time()