安装 tornado后仍旧提示 ImportError: No module named 'tornado'

sudo pip3 install tornado -i https://pypi.tuna.tsinghua.edu.cn/simple

安装 tornado后仍旧提示 ImportError: No module named 'tornado'

原因是本主机器上python3有两个版本 python3.5和python3.6，默认的python3 指向了python3.5，而tornado安装到了python3.6里，解决办法是：

vi ~/.bashrc

alias python3='/usr/bin/python3.6' #add this line into the file ~/.bashrc

source ~/.bashrc