安裝
sudo pip install flake8
$ flake8 hello.py
hello.py:4:1: E302 expected 2 blank lines, found 1
hello.py:4:11: E999 SyntaxError: invalid syntax
hello.py:5:5: E113 unexpected indentation
hello.py:7:1: E305 expected 2 blank lines after class or function definition, found 1
