old_contents: # -*- coding: utf-8 -*-
  from __future__ import absolute_import, unicode_literals
  
  from django.apps import AppConfig
  
  class MainAppConfig(AppConfig):
      name = 'commonrepo.main'
  
      def ready(self):
          import commonrepo.main.signals
  
new_contents: # -*- coding: utf-8 -*-
  from __future__ import absolute_import, unicode_literals
  
  from django.apps import AppConfig
  
  
  class MainAppConfig(AppConfig):
      name = 'commonrepo.main'
  
      def ready(self):
          import commonrepo.main.signals
  
subject: 更新 modules main/apps.py, 修正 PEP8 警告