old_contents: from django.contrib import admin
  from .models import Sponsor, SponsorGroup, MeetingSponsor, GeneralSponsor
  
  
  class MeetingSponsorInline(admin.StackedInline):
      extra = 0
      model = MeetingSponsor
  
  
  class GeneralSponsorAdmin(admin.ModelAdmin):
      model = GeneralSponsor
      list_display = ['sponsor', 'about_short']
  
  
  class SponsorAdmin(admin.ModelAdmin):
      list_display = ["name", "slug", ]
      search_fields = ["name", "slug", "url"]
      prepopulated_fields = {"slug": ("name",)}
  
  
  class SponsorGroupAdmin(admin.ModelAdmin):
      list_display = ["name"]
      search_fields = ["name"]
  
  
  admin.site.register(Sponsor, SponsorAdmin)
  admin.site.register(SponsorGroup, SponsorGroupAdmin)
  admin.site.register(GeneralSponsor, GeneralSponsorAdmin)
  
new_contents: from django.contrib import admin
  from .models import Sponsor, SponsorGroup, MeetingSponsor, GeneralSponsor
  
  
  class MeetingSponsorInline(admin.StackedInline):
      extra = 0
      model = MeetingSponsor
  
  
  class GeneralSponsorAdmin(admin.ModelAdmin):
      model = GeneralSponsor
      list_display = ['sponsor', 'about_short']
  
  
  class SponsorAdmin(admin.ModelAdmin):
      list_display = ["name", "slug", "sponsor_group"]
      list_filter = ["sponsor_group"]
      search_fields = ["name", "slug", "url"]
      prepopulated_fields = {"slug": ("name",)}
  
  
  class SponsorGroupAdmin(admin.ModelAdmin):
      list_display = ["name"]
      search_fields = ["name"]
  
  
  admin.site.register(Sponsor, SponsorAdmin)
  admin.site.register(SponsorGroup, SponsorGroupAdmin)
  admin.site.register(GeneralSponsor, GeneralSponsorAdmin)
  
subject: Add SponsorGroup to Sponsor admin list page