我试图在我的Jupyter Notebook中运行下面的基本示例代码。

import multiprocessing
import time

def square(x):
    print('=====> ',x)
    return x * x

if __name__ == "__main__":
    pool = multiprocessing.Pool()
    inputs = [0,1,2,3,4]
    outputs_async = pool.map_async(square, inputs)
    print(outputs_async)
    outputs = outputs_async.get(timeout=10)
    print("Output: {}".format(outputs))

我得到下面的输出

<multiprocessing.pool.MapResult object at 0x00000249E3A17188>
---------------------------------------------------------------------------
TimeoutError                              Traceback (most recent call last)
<ipython-input-3-f7d558819a08> in <module>
     12     outputs_async = pool.map_async(square, inputs)
     13     print(outputs_async)
---> 14     outputs = outputs_async.get(timeout=10)
     15     print("Output: {}".format(outputs))

~\Anaconda3\lib\multiprocessing\pool.py in get(self, timeout)
    651         self.wait(timeout)
    652         if not self.ready():
--> 653             raise TimeoutError
    654         if self._success:
    655             return self._value

TimeoutError:

看起来像这样，代码本身没有调用我的square方法。
请帮助如何解决这个问题。
谢啦