old_contents: from django.db.models.signals import post_save
  
  from .models import Comment, Post
  
  
  def save_comment(sender, instance, created, **kwargs):
      if created:
          comment = instance
          post = comment.post
          post.comment_count = post.comments.count()
          post.save(force_update=True)
  
new_contents: 
  
  def save_comment(sender, instance, created, **kwargs):
      if created:
          comment = instance
          post = comment.post
          post.comment_count = post.comments.count()
          post.save(force_update=True)
  
subject: Remove Unused imports