Using async/await keywords with Tk.after() method of tkinter

tk.after accepts a normal function, not a coroutine. To run the coroutine to completion, you can use run_until_complete, just as you did the first time:

loop = asyncio.get_event_loop()root.after(10000, lambda: loop.run_until_complete(updateLoans()))

Also, don't call loop.close(), since you'll need the loop again.

While Tkinter and asyncio cannot share an event loop yet, it is perfectly possible to run the asyncio event loop in a separate thread. The main thread then runs the GUI, while a dedicated asyncio thread runs all asyncio coroutines. When the event loop needs to notify the GUI to refresh something, it can use a queue as shown here. On the other hand, if the GUI needs to tell the event loop to do something, it can call call_soon_threadsafe or run_coroutine_threadsafe.

Example code (untested):

gui_queue = queue.Queue()async def updateLoans():    while True:        offers = await dd.loanOffers()        demands = await dd.loanDemands()        print('loans obtained')        gui_queue.put(lambda: updateLoansGui(offers, demands))        await asyncio.sleep(10)def updateLoansGui(offers, demands):    w.LoanOfferView.delete(1.0, END)    w.LoanDemandView.delete(1.0, END)    w.LoanOfferView.insert(END, offers)    w.LoanDemandView.insert(END, demands)    print('loans GUI refreshed')# http://effbot.org/zone/tkinter-threads.htmdef periodicGuiUpdate():    while True:        try:            fn = gui_queue.get_nowait()        except queue.Empty:            break        fn()    root.after(100, periodicGuiUpdate)# Run the asyncio event loop in a worker thread.def start_loop():    loop = asyncio.new_event_loop()    asyncio.set_event_loop(loop)    loop.create_task(updateLoans())    loop.run_forever()threading.Thread(target=start_loop).start()# Run the GUI main loop in the main thread.periodicGuiUpdate()root.mainloop()# To stop the event loop, call loop.call_soon_threadsafe(loop.stop).# To start a coroutine from the GUI, call asyncio.run_coroutine_threadsafe.