tkinter MP working like a charm - almost...

[Wu Xi]

from tkinter import * ; from tkinter import messagebox
import asyncio ,  random

async def one_url(url):  
    """ This is a multi threaded tkinter demo where tasks run in the background and aim to not freeze the tk GUI, py v3.7"""
    sec = random.randint(1, 8)
    await asyncio.sleep(sec  )
    return 'url: {}  took {}  seconds'.format(url, sec)

async def do_urls():                                       
    """ Creating and starting 10 tasks. """
    tasks   = [one_url(url)  for url  in    range(10)]
    completed, pending =     await asyncio.wait(tasks)
    results = [task.result() for task in    completed]
    print('\n'.join(results))

def do_nofreeze():     messagebox.showinfo(message='see, Tkinter is still responsive.')

def widgets(master):   Button(master, text='GUI Frozen?',   command=do_nofreeze).pack()

def tk_update(interval): 
    """ A production version of this should make it possible to cancel. However, when loop stops, updates will stop. T. Reedy"""
    loop.call_later(  interval,  root.update  )    
    root.update()

if __name__ == '__main__':
    root = Tk()
    widgets(root)
    loop = asyncio.get_event_loop()
    tk_update(.05)
    loop.run_until_complete(do_urls())  
    #                                   wow! no call to  root.mainloop()  anymore. somehow like in IDLE - but it freezes now :-(