use assert[Not]IsInstance where appropriate
diff --git a/Lib/test/test_threading.py b/Lib/test/test_threading.py
index 0360ea9..5daf822 100644
--- a/Lib/test/test_threading.py
+++ b/Lib/test/test_threading.py
@@ -154,8 +154,7 @@
# Wait for the thread to finish.
mutex.acquire()
self.assertIn(tid, threading._active)
- self.assertTrue(isinstance(threading._active[tid],
- threading._DummyThread))
+ self.assertIsInstance(threading._active[tid], threading._DummyThread)
del threading._active[tid]
# PyThreadState_SetAsyncExc() is a CPython-only gimmick, not (currently)