Weighted average

Returns the weighted average of two or more numbers.

• Use sum() to sum the products of the numbers by their weight and to sum the weights.
• Use zip() and a list comprehension to iterate over the pairs of values and weights.

def weighted_average(nums, weights):
  return sum(x * y for x, y in zip(nums, weights)) / sum(weights)

weighted_average([1, 2, 3], [0.6, 0.2, 0.3]) # 1.72727