Oh, I see, so its same as "a < b < c" but way more cryptic :)

python chains comparisons (google it) (and that can be very unintuitive when reading something like this)

Why does "ch==c in alphabet" work? But when you put parenthesis around any operator it stops working.

you don't need 'i' since it is always equal to a+1 :)

hello

This will give a ValueError for n=0

If there are no good ideas ("as is often the case") then it traverses array only once.