虽然已经装了，但一直报错 ,版本是3.1.1 最新版
➜ ~ pip install robotframework
DEPRECATION: Python 2.7 will reach the end of its life on January 1st, 2020. Please upgrade your Python as Python 2.7 won't be maintained after that date. A future version of pip will drop support for Python 2.7.
Requirement already satisfied: robotframework in /usr/local/lib/python2.7/site-packages (3.1.1)
解决办法：
卸载后，重新安装旧版本，测试用例可以执行
sudo pip uninstall robotframework
pip install robotframework==3.0