parse_ranges

I'd like you to write a function called parse_ranges, which accepts a string containing ranges of numbers and returns an iterable of those numbers.

The numeric ranges in the string will consist of two numbers separated by hyphens and each of the ranges will be separated by commas and any number of spaces.

Your function should work like this:

>>> parse_ranges('1-2,4-4,8-13')
[1, 2, 4, 8, 9, 10, 11, 12, 13]
>>> parse_ranges('0-0, 4-8, 20-20, 43-45')
[0, 4, 5, 6, 7, 8, 20, 43, 44, 45]

In the examples above the functions return lists of numbers. Your function can return any iterable of numbers that you'd like though.

If you finish the main problem, try to solve at least one of the bonuses.

Bonus 1