解决python安装第三方库速度很慢的问题(opencv为例)
pip install -i https://pypi.tuna.tsinghua.edu.cn/simple tensorflow==1.15 --no-cache-dir
pip install -i https://pypi.tuna.tsinghua.edu.cn/simple opencv-python --no-cache-dir
pip install -i https://pypi.tuna.tsinghua.edu.cn/simple tensorflow==1.15 --no-cache-dir
pip install -i https://pypi.tuna.tsinghua.edu.cn/simple opencv-python --no-cache-dir