Additional loop when stoping while loop

Question

I've created a function using the carriage return from this and threading trick to exit loop from this. The function will keep counting until a keystroke is detected.

Everything works fine except an additional line is printed whenever I kill the loop.

For example in console:

Press anything to stop it: 6 #<------------- pressed enter

Press anything to stop it: 7 #<------------- additional line produced

import _thread
import time
import sys

def input_thread(list):
    input()
    list.append(None)

def do_stuff():
    counter = 0
    list = []
    _thread.start_new_thread(input_thread,(list,))

    while not list:
        time.sleep(0.1)
        sys.stdout.write("Press anything to stop it: %d   \r" % (counter))
        sys.stdout.flush()
        counter += 1

How can I prevent extra line being printed? I suspect it has something to do with the while loop has to finish additional loop in order to exit. If the answer to this question is too obvious please let me know the keyword to search for. Thanks a million!