from typing import List def mean(nums: List) -> float: """ Find mean of a list of numbers. Wiki: https://en.wikipedia.org/wiki/Mean >>> mean([3, 6, 9, 12, 15, 18, 21]) 12.0 >>> mean([5, 10, 15, 20, 25, 30, 35]) 20.0 >>> mean([1, 2, 3, 4, 5, 6, 7, 8]) 4.5 >>> mean([]) Traceback (most recent call last): ... ValueError: List is empty """ if not nums: raise ValueError("List is empty") return sum(nums) / len(nums) if __name__ == "__main__": import doctest doctest.testmod()