我用的是ubuntu16版本自帶的python3.5，pip install mitmproxy過後使用mitmdump -V驗證是否可用時，系統提示需要python3.6以上版本，在升級到python3.6後又重新安裝，在 pip 過程中卻又冒出這麼一個玩意：
Found existing installation: blinker 1.3
Cannot uninstall 'blinker'. It is a distutils installed project and thus we cannot accurately determine which files belong to it which would lead to only a partial uninstall.
解決辦法：
sudo apt-get remove blinker
sudo -H pip install --ignore-installed -U blinker
最後再一次pip install mitmproxy，沒有再出什麼幺蛾子