def setdefault(self, key, default=None):
        """Set `default` if the key is not in the cache otherwise
        leave unchanged. Return the value of this key.
        """
        try:
            return self[key]
        except __HOLE__:
            self[key] = default
            return default
dataset/ETHPy150Open AppScale/appscale/AppServer/lib/jinja2-2.6/jinja2/utils.py/LRUCache.setdefault