> Boolean is a subclass of Integer, because... why?

truth/falsity is more general than that in python, so bools aren't really necessary.

As for why, 0 is false, nonzero is true (not 1, any non-zero). So false is 'nothing there' and true is 'something is there'. This generalises to other structures, an empty list is nothing (ie. false) a non-empty list is not-nothing so is true so you can do

  >>> y = [23, 24, 25]
  >>> while y:
  ...   print(y)
  ...   y = y[1:]
  ...
  [23, 24, 25]
  [24, 25]
  [25]

Ditto loadsa other things.

I guess this was a lisp inheritance.