WARNING: You are using pip version 19.3.1; however, version 20.0.2 is available.

今天使用python命令行出现

WARNING: You are using pip version 19.3.1; however, version 20.0.2 is available.
You should consider upgrading via the 'python -m pip install --upgrade pip' command.

作为一个强迫症，当然是不能忍，必须升级到最新的。

然而按照提示输入

python -m pip install --upgrade pip

却出现了

PS C:\Users\Vincent> python -m pip install --upgrade pip
Collecting pip
  Using cached https://files.pythonhosted.org/packages/54/0c/d01aa759fdc501a58f431eb594a17495f15b88da142ce14b5845662c13f
3/pip-20.0.2-py2.py3-none-any.whl
Installing collected packages: pip
  Found existing installation: pip 19.3.1
    Uninstalling pip-19.3.1:
      Successfully uninstalled pip-19.3.1
  Rolling back uninstall of pip
  Moving to c:\users\vincent\appdata\roaming\python\python38\scripts\pip.exe
   from C:\Users\Vincent\AppData\Local\Temp\pip-uninstall-sus0si9z\pip.exe
  Moving to c:\users\vincent\appdata\roaming\python\python38\scripts\pip3.8.exe
   from C:\Users\Vincent\AppData\Local\Temp\pip-uninstall-sus0si9z\pip3.8.exe
  Moving to c:\users\vincent\appdata\roaming\python\python38\scripts\pip3.exe
   from C:\Users\Vincent\AppData\Local\Temp\pip-uninstall-sus0si9z\pip3.exe
  Moving to c:\users\vincent\appdata\roaming\python\python38\site-packages\pip-19.3.1.dist-info\
   from C:\Users\Vincent\AppData\Roaming\Python\Python38\site-packages\~ip-19.3.1.dist-info
  Moving to c:\users\vincent\appdata\roaming\python\python38\site-packages\pip\
   from C:\Users\Vincent\AppData\Roaming\Python\Python38\site-packages\~ip
ERROR: Exception:
Traceback (most recent call last):
  File "C:\Users\Vincent\AppData\Roaming\Python\Python38\site-packages\pip\_internal\cli\base_command.py", line 153, in
_main
    status = self.run(options, args)
  File "C:\Users\Vincent\AppData\Roaming\Python\Python38\site-packages\pip\_internal\commands\install.py", line 446, in
run
    installed = install_given_reqs(
  File "C:\Users\Vincent\AppData\Roaming\Python\Python38\site-packages\pip\_internal\req\__init__.py", line 58, in insta
ll_given_reqs
    requirement.install(
nstall
    self.move_wheel_files(
  File "C:\Users\Vincent\AppData\Roaming\Python\Python38\site-packages\pip\_internal\req\req_install.py", line 487, in move_wheel_files
    wheel.move_wheel_files(
  File "C:\Users\Vincent\AppData\Roaming\Python\Python38\site-packages\pip\_internal\wheel.py", line 594, in move_wheel_files
    generated_console_scripts = maker.make_multiple(scripts_to_generate)
  File "C:\Users\Vincent\AppData\Roaming\Python\Python38\site-packages\pip\_vendor\distlib\scripts.py", line 402, in make_multiple
    filenames.extend(self.make(specification, options))
  File "C:\Users\Vincent\AppData\Roaming\Python\Python38\site-packages\pip\_internal\wheel.py", line 330, in make
    return super(PipScriptMaker, self).make(specification, options)
  File "C:\Users\Vincent\AppData\Roaming\Python\Python38\site-packages\pip\_vendor\distlib\scripts.py", line 391, in make
    self._make_script(entry, filenames, options=options)
  File "C:\Users\Vincent\AppData\Roaming\Python\Python38\site-packages\pip\_vendor\distlib\scripts.py", line 295, in _make_script
    self._write_script(scriptnames, shebang, script, filenames, ext)
  File "C:\Users\Vincent\AppData\Roaming\Python\Python38\site-packages\pip\_vendor\distlib\scripts.py", line 231, in _write_script
    launcher = self._get_launcher('t')
  File "C:\Users\Vincent\AppData\Roaming\Python\Python38\site-packages\pip\_vendor\distlib\scripts.py", line 370, in _ge    result = finder(distlib_package).find(name).bytes
AttributeError: 'NoneType' object has no attribute 'bytes'
WARNING: You are using pip version 19.3.1; however, version 20.0.2 is available.
You should consider upgrading via the 'python -m pip install --upgrade pip' command.