升级pip报错

ERROR: Exception:
Traceback (most recent call last):
File "C:UsersadminAppDataRoamingPythonPython37site-packagespip\_internalcliase_command.py", line 178, in main
status = self.run(options, args)
File "C:UsersadminAppDataRoamingPythonPython37site-packagespip\_internalcommandsinstall.py", line 414, in run
use_user_site=options.use_user_site,
File "C:UsersadminAppDataRoamingPythonPython37site-packagespip\_internal eq\__init__.py", line 58, in install_given_reqs
**kwargs
File "C:UsersadminAppDataRoamingPythonPython37site-packagespip\_internal eq eq_install.py", line 920, in install
use_user_site=use_user_site, pycompile=pycompile,
File "C:UsersadminAppDataRoamingPythonPython37site-packagespip\_internal eq eq_install.py", line 448, in move_wheel_files
warn_script_location=warn_script_location,
File "C:UsersadminAppDataRoamingPythonPython37site-packagespip\_internalwheel.py", line 544, in move_wheel_files
generated.extend(maker.make(spec))
File "C:UsersadminAppDataRoamingPythonPython37site-packagespip\_vendordistlibscripts.py", line 405, in make
self._make_script(entry, filenames, options=options)
File "C:UsersadminAppDataRoamingPythonPython37site-packagespip\_vendordistlibscripts.py", line 309, in _make_script
self._write_script(scriptnames, shebang, script, filenames, ext)
File "C:UsersadminAppDataRoamingPythonPython37site-packagespip\_vendordistlibscripts.py", line 245, in _write_script
launcher = self._get_launcher('t')
File "C:UsersadminAppDataRoamingPythonPython37site-packagespip\_vendordistlibscripts.py", line 384, in _get_launcher
result = finder(distlib_package).find(name).bytes
AttributeError: 'NoneType' object has no attribute 'bytes'
WARNING: You are using pip version 19.1.1, however version 19.2.3 is available.
You should consider upgrading via the 'python -m pip install --upgrade pip' command.

用easy_install -U pip命令就可以正常升级了