def __getitem__(self, key):
        """Get an item from the cache. Moves the item up so that it has the
        highest priority then.

        Raise an `KeyError` if it does not exist.
        """
        rv = self._mapping[key]
        if self._queue[-1] != key:
            try:
                self._remove(key)
            except __HOLE__:
                # if something removed the key from the container
                # when we read, ignore the ValueError that we would
                # get otherwise.
                pass
            self._append(key)
        return rv
dataset/ETHPy150Open AppScale/appscale/AppServer/lib/jinja2-2.6/jinja2/utils.py/LRUCache.__getitem__