Also love how he aliases `str.split` to `Keypad` so you can see the intention of his semantics that much more easily. And the assertion of keypad[2][2], as a qu

Also love how he aliases `str.split` to `Keypad` so you can see the intention of his semantics that much more easily. And the assertion of keypad[2][2], as a quick reference point for himself. The whole thing is just so eminently understandable.