Python process pooling

pooling.py

from multiprocessing import Pool

def func(a):  # in case you want to pass multiple arguments, pack them by making a data type, or use starmap
    b = a**2
    return a, b  # return the argument in addition to the result for convenience

with Pool(20) as p:
    output = {k: v for k, v in p.imap(func, range(100))}

For imap, imap_unordered, and map_async, refer to https://stackoverflow.com/questions/26520781/multiprocessing-pool-whats-the-difference-between-map-async-and-imap