This fixes typos related to the word "hexadecimal"

I did notice also you are hardcoding the hex digits, I didn't include it in this scope, but you can simply use string.hexdigits (see https://docs.python.org/3/library/string.html#string.hexdigits for Python 3 and https://docs.python.org/2/library/string.html#string.hexdigits for Python 2) as a constant instead (this also applies to other constant values.