test.py

from multiprocessing import Pool
import requests


def process_url(url):
    print('start')
    requests.get(url)
    print('done')
    return


if __name__ == '__main__':
    urls_to_download = 'https://baidu.com'
    PARALLEL_WORKERS = 1

    pool = Pool(PARALLEL_WORKERS)
    result = pool.apply_async(process_url, (urls_to_download,))
    result.get()
    pool.close()
    pool.join()