old_contents: from django.contrib import admin
  
  from .models import Identity, OptOut, OptIn
  
  admin.site.register(Identity)
  admin.site.register(OptOut)
  admin.site.register(OptIn)
  
new_contents: from django.contrib import admin
  
  from .models import Identity, OptOut, OptIn
  
  
  class IdentityAdmin(admin.ModelAdmin):
      list_display = ["id", "created_at", "updated_at", "created_by",
                      "updated_by"]
      list_filter = ["created_at"]
  
  
  class OptOutAdmin(admin.ModelAdmin):
      list_display = ["id", "identity", "optout_type", "address_type", "address",
                      "reason", "created_at", "created_by"]
      list_filter = ["optout_type", "address_type", "reason", "created_at",
                     "created_by"]
      search_fields = ["identity__id", "address"]
  
  
  class OptInAdmin(admin.ModelAdmin):
      list_display = ["id", "identity", "address_type", "address",
                      "created_at", "created_by"]
      list_filter = ["address_type", "created_at", "created_by"]
      search_fields = ["identity__id", "address"]
  
  
  admin.site.register(Identity, IdentityAdmin)
  admin.site.register(OptOut, OptOutAdmin)
  admin.site.register(OptIn, OptInAdmin)
  
subject: expand admin view