问木星笔记本和md5sum是否存在已知的问题？

EN

def pipe(cmd):
     """Runs a command in a subprocess.

     cmd: string Unix command

     Returns (res, stat), the output of the subprocess and the exit status.
"""
     # Note: os.popen is deprecated
     # now, which means we are supposed to stop using it and start using
     # the subprocess module.  But for simple cases, I find
     # subprocess more complicated than necessary.  So I am going
     # to keep using os.popen until they take it away.

     fp = os.popen(cmd)
     res = fp.read()
     stat = fp.close()
     assert stat is None
     return res, stat

cmd= 'md5sum ' + 'words.txt'
pipe(cmd)

---------------------------------------------------------------------------
AssertionError                            Traceback (most recent call last)
<ipython-input-137-ccd8fd0ce9f8> in <module>
     18     return res, stat
     19 cmd= 'md5sum ' + 'words.txt'
---> 20 pipe(cmd)

<ipython-input-137-ccd8fd0ce9f8> in pipe(cmd)
     15     res = fp.read()
     16     stat = fp.close()
---> 17     assert stat is None
     18     return res, stat
     19 cmd= 'md5sum ' + 'words.txt'

AssertionError: