Reminder~
The data sources of the domestic python installation library are:
1. pip install packagename -i https://pypi.douban.com/simple/
2. pip install packagename -i https://pypi.tuna.tsinghua.edu.cn/simple
3. pip install packagename -ihttps://mirrors.aliyun.com/pypi/simple/
If it still cannot be installed, you can choose the following method to install:
pip install packagename -i http://pypi.douban.com/simple/ --trusted-host pypi.douban.com