import multiprocessing
import gc
import _thread
import threading

before = _thread._count(), threading._dangling.copy()
q = multiprocessing.Queue()
q.put(1)
x = q.get()
q = None
# oops, I didn't close the queue and I didn't join the thread!
gc.collect()
after = _thread._count(), threading._dangling.copy()

print("number of thread diff: %+i" % (after[0] - before[0]))
if after[1] != before[1]:
    print("dangling threads!")
    print("before:", list(before[1]))
    print("after:", list(after[1]))