直接看下面实例：
In [52]: output=subprocess.check_output(["head -c 16 /dev/urandom | od -An -t x | tr -d ' '"], shell=True)
In [53]: print(output)
b'3512c668547cd983cb48ccf05b0ccedf\n'
In [67]: output.strip()
Out[67]: b'3512c668547cd983cb48ccf05b0ccedf'
In [72]: output.strip().strip('b')
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)
<ipython-input-72-d12ac1d7dec8> in <module>
----> 1 output.strip().strip('b')
TypeError: a bytes-like object is required, not 'str'
In [70]: str(output.strip()).strip('b')
Out[70]: "'3512c668547cd983cb48ccf05b0ccedf'"