How to process a list in batches of pairwise using iter() and next()

threads_pairwise.py

#!/usr/local/env/ python
# -*- coding:utf-8 -*-

import sys
import time
from threading import Thread, current_thread
#from queue import Queue

lista = [1,3,6,4,3]

def main():

    iterlist = iter(lista)
    for i in iterlist:
        print("Processing thread with wait of: " + str(i))
        t = Thread(target=thread_function, args=(i,))
        #t.daemon = True
        t.start()

        next(iterlist)

        print("Processing thread with wait of: " + str(i))
        t = Thread(target=thread_function, args=(i,))
        #t.daemon = True
        t.start()

        time.sleep(2)

def thread_function(item):
    if item:
        print("Running " + current_thread().name)
        if len(sys.argv) > 1 and sys.argv[1] in ["--wait", "-W"]:
            print("wait " + str(item))
            time.sleep(item)
        print(current_thread().name + "finished")

if __name__ == "__main__":
    main()