<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _set_as_cached(self, item, cacher):
 """Set the _cacher attribute on the calling object with a weakref to cacher. """

        self._cacher = (item, weakref.ref(cacher))