def mall(self):
"""
Stores the mall key as a cached a property
"""
mall_key = memcache.get_mall_key()
if mall_key:
return mall_key
else:
mall = Mall.get_or_create()
if mall:
mall_key = ndb.Key(mall.key.kind(), mall.key.id())
memcache.set_mall_key(mall_key)
return mall_key
return None
