Windows pip upgrade 报错 No module named 'pip'

pip install -U pip

pip install --upgrade pip --user

python -m ensurepip
python -m pip install --upgrade pip

$ pip list
Traceback (most recent call last):
  File "e:\program_files\annoconda\lib\runpy.py", line 193, in _run_module_as_main
    "__main__", mod_spec)
  File "e:\program_files\annoconda\lib\runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "E:\Program_Files\Annoconda\Scripts\pip.exe\__main__.py", line 4, in <module>
ModuleNotFoundError: No module named 'pip'

$ python -m ensurepip
Looking in links: C:\Users\Admin\AppData\Local\Temp\tmp1ggp6o2t
Requirement already satisfied: setuptools in e:\program_files\annoconda\lib\site-packages (45.1.0)
Collecting pip
jupyterlab 2.1.0 has requirement jupyterlab_server>=1.1.0, but you'll have jupyterlab-server 1.0.0 which is incompatible.
jupyterlab-server 1.0.0 has requirement jsonschema>=3.0.1, but you'll have jsonschema 2.6.0 which is incompatible.
imgviz 1.1.0 has requirement Pillow>=5.3.0, but you'll have pillow 5.2.0 which is incompatible.
Installing collected packages: pip
Successfully installed pip-10.0.1

$ python -m pip install --upgrade pip
Looking in indexes: https://mirrors.aliyun.com/pypi/simple/
Collecting pip
  Using cached https://mirrors.aliyun.com/pypi/packages/43/84/23ed6a1796480a6f1a2d38f2802901d078266bda38388954d01d3f2e821d/pip-20.1.1-py2.py3-none-any.whl
jupyterlab 2.1.0 has requirement jupyterlab_server>=1.1.0, but you'll have jupyterlab-server 1.0.0 which is incompatible.
jupyterlab-server 1.0.0 has requirement jsonschema>=3.0.1, but you'll have jsonschema 2.6.0 which is incompatible.
imgviz 1.1.0 has requirement Pillow>=5.3.0, but you'll have pillow 5.2.0 which is incompatible.
Installing collected packages: pip
  Found existing installation: pip 10.0.1
    Uninstalling pip-10.0.1:
      Successfully uninstalled pip-10.0.1
Successfully installed pip-20.1.1
You are using pip version 20.1.1, however version 20.2b1 is available.
You should consider upgrading via the 'python -m pip install --upgrade pip' command.