You are using pip version 8.1.1, however version 10.0.1 is available. You should consider upgrading via the 'pip install --upgrade pip' install。

 升级pip3

1.输入升级指令

sudo pip3 install --upgrade pip

注意：如果只进行这一步的话接下来的安装仍会报错，提示错误大致为：cannot import name 'main'。所以还需要修改/usr/bin/pip3文件，见第二步。 

2.修改配置文件

sudo gedit /usr/bin/pip3

 改成如下（最后一行和倒数第三行）：

#!/usr/bin/python3
# GENERATED BY DEBIAN

import sys

# Run the main entry point, similarly to how setuptools does it, but because
# we didn't install the actual entry point from setup.py, don't use the
# pkg_resources API.
from pip import __main__
if __name__ == '__main__':
    sys.exit(__main__.main())