proxy環境でpipを実行する＠python

python -m pip install --trusted-host pypi.python.org --trusted-host files.pythonhosted.org --trusted-host pypi.org pip --upgrade pip
Collecting pip
  Downloading pip-20.3.1-py2.py3-none-any.whl (1.5 MB)
     |████████████████████████████████| 1.5 MB 1.6 MB/s
Installing collected packages: pip
  Attempting uninstall: pip
    Found existing installation: pip 20.2.3
    Uninstalling pip-20.2.3:
      Successfully uninstalled pip-20.2.3
Successfully installed pip-20.3.1