pyHook library Pyhook.PumpWaitingMessages returns nothing

Question

So, I've been trying to play with this a little, and I have this next bit of code

def KeyboardEvent(event):
    global log
    log.append(chr(event.Ascii))
    print log
    return True

hooks_manager = pyHook.HookManager()
hooks_manager.KeyDown = KeyboardEvent
hooks_manager.HookKeyboard()
pythoncom.PumpMessages()

Whenever I write something, I automatically get it printed out to me.

However, I want to to have stopping condition for the pumping. I've looked online, and found that I can replace pythoncom.PumpMessages() with pythoncom.PumpWaitingMessages() and then I can put it in a while loop.

However, When I run the exact same code with pythoncom.PumpWaitingMessages() inside a while True loop, all I get when i print log is nothing. null, empty spaces, weird Ascii things I can't understand, or stuff like this

['\x00', '\x00', '\x00', '\x00', '\x00', '\x00', '\x00', '\x00', '\x00']

I have no idea why this happens, The only thing I need is to find a way to stop pumping messages when I needed.