Code review comment for lp://qastaging/~james-page/charm-helpers/caching_hookenv

Good stuff.

I have very slight reservations about the way that flush works because it's very imprecise about the keys it removes. It doesn't matter now, but it could be confusing if someone were to extend the module in the future. It's also arguable whether it would really matter if the cache was cleared unexpectedly.

+1