old_contents: from django.contrib import admin
  from .models import (Sport, Match, Session, CancelledSession)
  
  @admin.register(Sport)
  class SportAdmin(admin.ModelAdmin):
      prepopulated_fields = {'slug': ('name',)}
  
      class Media:
          js = ('tinymce/tinymce.min.js', 'js/tinymce_4_config.js')
  
  @admin.register(Match)
  class MatchAdmin(admin.ModelAdmin):
  
      class Media:
          js = ('tinymce/tinymce.min.js', 'js/tinymce_4_config.js')
  
  @admin.register(CancelledSession)
  class CancelledSessionAdmin(admin.ModelAdmin):
  
      class Media:
          js = ('tinymce/tinymce.min.js', 'js/tinymce_4_config.js')
  
  admin.site.register(Session)
  
new_contents: from django.contrib import admin
  from .models import (Sport, Match, Session, CancelledSession)
  
  class SessionInline(admin.StackedInline):
      model = Session
      extra = 0
  
  @admin.register(Sport)
  class SportAdmin(admin.ModelAdmin):
      prepopulated_fields = {'slug': ('name',)}
      inlines = [SessionInline,]
  
      class Media:
          js = ('tinymce/tinymce.min.js', 'js/tinymce_4_config.js')
  
  @admin.register(Match)
  class MatchAdmin(admin.ModelAdmin):
  
      class Media:
          js = ('tinymce/tinymce.min.js', 'js/tinymce_4_config.js')
  
  @admin.register(CancelledSession)
  class CancelledSessionAdmin(admin.ModelAdmin):
  
      class Media:
          js = ('tinymce/tinymce.min.js', 'js/tinymce_4_config.js')
  
subject: Move Session to Sport as an inline.