old_contents: from django.contrib import admin
  from questions.models import Question, Comments
  
  
  class QuestionInline(admin.StackedInline):
      """Class for adding comments to question."""
      model = Comments
      extra = 2
  
  
  class QuestionAdmin(admin.ModelAdmin):
      """Class for administration Question objects."""
      inlines = [QuestionInline]
      list_filter = ['created_on']
  
  admin.site.register(Question, QuestionAdmin)
  
new_contents: from django.contrib import admin
  from questions.models import Question, Comments
  
  
  class QuestionInline(admin.StackedInline):
      """Class for adding comments to question."""
      model = Comments
      extra = 2
  
  
  @admin.register(Question)
  class QuestionAdmin(admin.ModelAdmin):
      """Class for administration Question objects."""
      inlines = [QuestionInline]
      list_filter = ['created_on']
  
subject: Use decorator @admin.register to regstrate