<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def setter(self, can_set=None):
 """ Like `CachedProp.deleter` is for `CachedProp.can_delete`, but for `can_set` :param can_set: boolean to change to it, and None to toggle :type can_set: Optional[bool] :return: self, so this can be used as a decorator like a `property` :rtype: CachedProperty """

        if can_set is None:
            self._setter = not self._setter
        else:
            self._setter = bool(can_set)
        # For use as decorator
        return self