Sum comprehension

Sourcery refactoring id: sum-comprehension

Description:

Replaces summed values created with for loops with sum comprehensions

Before:

total = 0
for hat in hats:
    total += hat.price

After:

total = sum(hat.price for hat in hats)

Explanation:

Much of programming is about adding up lists of things, and Python has the built-in sum() function to help with this.

This is much shorter, which is a definite bonus. The code also now explicitly tells you what it is trying to do - sum the price of all the hats.