Python类和方法注释规范
参考:Python风格规范 — Google 开源项目风格指南
http://zh-google-styleguide.readthedocs.io/en/latest/google-python-styleguide/python_style_rules/#comments
参考:Python风格规范 — Google 开源项目风格指南
http://zh-google-styleguide.readthedocs.io/en/latest/google-python-styleguide/python_style_rules/#comments