Computes the product of the elements of A. complexity: O(n), where n is the number of elements in A.

Prod.py

# python 3.6.5
# from typing import List
def prod( A: List[int] ) -> int:
    """ Computes the product of the elements of A. """
    if A == None or len(A) == 0:
        return 0
    z: int = 1
    for a in A:
        z *= a
    return z