"""
# Here we can see how a decision not to return the modified map
# leads to a need for a hack.
- return reduce(lambda a, b: a.update(b) or a, self._options, defaultdict(lambda: False))
+ return reduce(lambda a, b: a.update(b) or a, self._options, defaultdict(lambda: None))
@options.setter
def options(self, opts):