安装python3.5：
添加 PPA：
sudo add-apt-repository ppa:fkrull/deadsnakes
sudo apt-get update
sudo apt-get install python3.5
sudo apt-get install python3.5-dev
sudo cp /usr/bin/python /usr/bin/python_bak，先备份
sudo rm /usr/bin/python,删除
sudo ln -s /usr/bin/python3.5 /usr/bin/python，默认设置成python3.5
安装新版pip：
wget https://bootstrap.pypa.io/get-pip.py
sudo python3 get-pip.py
sudo pip3 install setuptools --upgrade
sudo pip3 install ipython[all]
