Python-сообщество

 sem = threading.Semaphore(S_THREADS)
thr_lst = []
for ind, mail_to in enumerate(mail_list):
    if ind > 0 and ind % int(S_COUNTER_OF_SENT_EMAILS) == 0:
        send_for_my_email()
        print(f'Pause time = {S_PAUSE_TIME} sec')
        time.sleep(S_PAUSE_TIME)
    thr = threading.Thread(
        target=run_smtp_send_with_semaphore,
        args=(mail_to, sem),
        daemon=True
    )
    thr_lst.append(thr)
    thr.start()
[i_thr.join() for i_thr in thr_lst]