Windows下升级pip推荐的方式为：
$ python -m pip install --upgrade pip这样操作却往往会出现下面的错误：
Exception:
Traceback (most recent call last):
File "D:Kangbeibeipython_projectdatamining-learningdecision_treevenvlibsite-packagespip-9.0.3-py3.6.eggpipasecommand.py", line 215, in main
status = self.run(options, args)
File "D:Kangbeibeipython_projectdatamining-learningdecision_treevenvlibsite-packagespip-9.0.3-py3.6.eggpipcommandsinstall.py", line 342, in run
prefix=options.prefix_path,
File "D:Kangbeibeipython_projectdatamining-learningdecision_treevenvlibsite-packagespip-9.0.3-py3.6.eggpip
eq
eq_set.py", line 784, in install
**kwargs
File "D:Kangbeibeipython_projectdatamining-learningdecision_treevenvlibsite-packagespip-9.0.3-py3.6.eggpip
eq
eq_install.py", line 851, in install
self.move_wheel_files(self.source_dir, root=root, prefix=prefix)
File "D:Kangbeibeipython_projectdatamining-learningdecision_treevenvlibsite-packagespip-9.0.3-py3.6.eggpip
eq
eq_install.py", line 1064, in move_wheel_files
isolated=self.isolated,
File "D:Kangbeibeipython_projectdatamining-learningdecision_treevenvlibsite-packagespip-9.0.3-py3.6.eggpipwheel.py", line 462, in move_wheel_files
generated.extend(maker.make(spec))
File "D:Kangbeibeipython_projectdatamining-learningdecision_treevenvlibsite-packagespip-9.0.3-py3.6.eggpip\_vendordistlibscripts.py", line 372, in make
self._make_script(entry, filenames, options=options)
File "D:Kangbeibeipython_projectdatamining-learningdecision_treevenvlibsite-packagespip-9.0.3-py3.6.eggpip\_vendordistlibscripts.py", line 276, in _make_script
self._write_script(scriptnames, shebang, script, filenames, ext)
File "D:Kangbeibeipython_projectdatamining-learningdecision_treevenvlibsite-packagespip-9.0.3-py3.6.eggpip\_vendordistlibscripts.py", line 212, in _write_script
launcher = self._get_launcher(‘t‘)
File "D:Kangbeibeipython_projectdatamining-learningdecision_treevenvlibsite-packagespip-9.0.3-py3.6.eggpip\_vendordistlibscripts.py", line 351, in _get_launcher
result = finder(distlib_package).find(name).bytes
AttributeError: ‘NoneType‘ object has no attribute ‘bytes‘可以采用下面的安装方式解决：
$ python -m pip install -U --force-reinstall pip