pip报错：TypeError: unsupported operand type(s) for -=: ‘Retry’ and 'int
TypeError: unsupported operand type(s) for -=: ‘Retry’ and ‘int’
You are using pip version 8.1.1, however version 20.0.2 is available.
You should consider upgrading via the ‘pip install --upgrade pip’ command.
解决方案
但是执行了pip install -upgrade pip 还是会报错，这个pip install是python2的pip，python3的pip需要更新的最新版。解决办法是：
sudo python -m pip install --upgrade --force pip 或者
sudo python3 -m pip install --upgrade --force pip