multithreading - Pythonスレッドでpyttsxを使用する方法

Question

私はpyttsx3テキスト読み上げのために働いています。スレッド内で使用できることに気付きました (または何か間違ったことをしています)。なぜなのかご存知ですか？

コード例:

from threading import Thread
import pyttsx3

def myfunc():
  engine = pyttsx3.init()
  engine.say("ok")
  engine.runAndWait()

t = Thread(target=myfunc)
t.start()

エラー：

 File "/usr/local/Cellar/python3/3.6.4/Frameworks/Python.framework/Versions/3.6/lib/python3.6/threading.py", line 916, in _bootstrap_inner
    self.run()
  File "/usr/local/Cellar/python3/3.6.4/Frameworks/Python.framework/Versions/3.6/lib/python3.6/threading.py", line 864, in run
    self._target(*self._args, **self._kwargs)
  File "test.py", line 9, in myfunc
    engine.runAndWait() #blocks
  File "/usr/local/lib/python3.6/site-packages/pyttsx3/engine.py", line 188, in runAndWait
    self.proxy.runAndWait()
  File "/usr/local/lib/python3.6/site-packages/pyttsx3/driver.py", line 204, in runAndWait
    self._driver.startLoop()
  File "/usr/local/lib/python3.6/site-packages/pyttsx3/drivers/nsss.py", line 33, in startLoop
    AppHelper.runConsoleEventLoop()
  File "/usr/local/lib/python3.6/site-packages/PyObjCTools/AppHelper.py", line 241, in runConsoleEventLoop
    nextfire = nextfire.earlierDate_(soon)
AttributeError: 'NoneType' object has no attribute 'earlierDate_'