SQL systems are weird in how they handle NULLs. You can't just "SELECT x FROM table1 WHERE y is NULL", you have to instead find a way to exclude all non-null values. Annoying, but I've just learned to accept it.

Remember that an 88-key piano starts at A, not C. That threw me off

Way late here, but for anyone else reading this: An <odd> % 2 == 1, and an <even> % 2 == 0, both of which can be interpreted as the boolean True (1) and False (0) in Python, respectively. So line 3 is essentially saying odd = True, even = False.

Extremely easy kata with extremely bad wording. Also, the singular form of "dice", is "die", which would have made this kata less confusing.

This is a frequent solution for more complicated strings

madman