Silly multiprocessing example

primes.py

#!/usr/bin/env python3
import sys
from argparse import ArgumentParser, Namespace
from multiprocessing import Pool
import math


def is_prime(maybe_prime: int) -> bool:
    for i in range(2, maybe_prime):
        if (maybe_prime % i) == 0:
            return False
    return True


def parse_args() -> Namespace:
    ap = ArgumentParser()
    ap.add_argument("n", type=int)
    ap.add_argument("-j", "--nproc", type=int, default=1)
    return ap.parse_args()


def main() -> None:
    args = parse_args()

    with Pool(processes=args.nproc) as pool:
        total = sum(pool.map(is_prime, range(2, args.n)))

    print(f"There are {total} prime numbers less than {args.n}")


if __name__ == "__main__":
    main()