# De Morgan's Laws

This just reminded me of something I forgot the name of, that not ((not a) or (not b)) is equivalent to a and b, and the same with and and or swapped.

More usually written as (not a) or (not b) = not (a and b).

Your way is right, too, of course, but in practice you're unlikely to stumble upon not ((not a) or (not b)), whereas it's fairly common to need to compute not (a and b).

Turns out I had exactly that:

if (not self.world.is_dev_mode and

if not (self.world.is_dev_mode or