def METHOD_NAME(self):
    for inst in popen2._active:
        inst.wait()
    popen2._cleanup()
    self.assertFalse(popen2._active, "popen2._active not empty")
    # The os.popen*() API delegates to the subprocess module (on Unix)
    import subprocess
    for inst in subprocess._active:
        inst.wait()
    subprocess._cleanup()
    self.assertFalse(subprocess._active, "subprocess._active not empty")
    reap_children()