Given a series of numbers in an array, find the missing number.
The array contains distinct integers from 0 through n, with exactly one value missing. Return the missing integer.
Use def missing_number(nums):, where nums is a list of integers and the return value is an integer.
Examples: nums = [3, 0, 1] returns 2; nums = [0, 1] returns 2.
Constraints: 0 <= len(nums) <= 1000, and every value is distinct and belongs to the range 0 through n.
def missing_number(nums):