参考 https://stackoverflow.com/questions/37495375/python-pip-install-throws-typeerror-unsupported-operand-types-for-retry/46970344#46970344
apt-get remove python-pip python3-pip
wget https://bootstrap.pypa.io/get-pip.py
python get-pip.py
python3 get-pip.py
如果运行get-pip.py很慢，修改文件中的args = ["install", "--upgrade", "--force-reinstall", "-i", "https://pypi.douban.com/simple"] + args，新增了pip源即可。
