解决方法:
1、升级pip :python -m pip install --upgrade pip
2、更换镜像源
pip install robotframework-selenium2library -i https://pypi.mirrors.ustc.edu.cn/simple

解决方法:
1、升级pip :python -m pip install --upgrade pip
2、更换镜像源
pip install robotframework-selenium2library -i https://pypi.mirrors.ustc.edu.cn/simple