Open the right way:
pip install -i https://pypi.tuna.tsinghua.edu.cn/simple --upgrade pip
Explanation
pip install -i https://pypi.tuna.tsinghua.edu.cn/simple *libname*
libname is the name of our tripartite need to install the library
Open the right way:
pip install -i https://pypi.tuna.tsinghua.edu.cn/simple --upgrade pip
pip install -i https://pypi.tuna.tsinghua.edu.cn/simple *libname*
libname is the name of our tripartite need to install the library