python 版本升级，遇到问题及解决
问题： You are using pip version 9.0.3, however version 19.0.2 is available.
You should consider upgrading via the 'python -m pip install --upgrade pip' command.
解决方案: 执行命令 python -m pip install --upgrade pip
pip命令找不见时： ModuleNotFoundError: No module named 'pip'
解决方案： 如果是：windows
cmd中敲命令：python -m ensurepip
得到pip的setuptools
然后就可以用：easy_install pip