old_contents: from django.contrib import admin
  from .models import Source, Registration, SubscriptionRequest
  
  
  class RegistrationAdmin(admin.ModelAdmin):
      list_display = [
          "id", "reg_type", "validated", "registrant_id", "source",
          "created_at", "updated_at", "created_by", "updated_by"]
      list_filter = ["source", "validated", "created_at"]
      search_fields = ["registrant_id", "data"]
  
  
  class SubscriptionRequestAdmin(admin.ModelAdmin):
      list_display = [
          "id", "identity", "messageset", "next_sequence_number", "lang",
          "schedule", "created_at", "updated_at"]
      list_filter = ["messageset", "created_at"]
      search_fields = ["identity"]
  
  
  admin.site.register(Source)
  admin.site.register(Registration, RegistrationAdmin)
  admin.site.register(SubscriptionRequest, SubscriptionRequestAdmin)
  
new_contents: from django.contrib import admin
  from .models import Source, Registration, SubscriptionRequest
  from .tasks import remove_personally_identifiable_fields
  
  
  class RegistrationAdmin(admin.ModelAdmin):
      list_display = [
          "id", "reg_type", "validated", "registrant_id", "source",
          "created_at", "updated_at", "created_by", "updated_by"]
      list_filter = ["source", "validated", "created_at"]
      search_fields = ["registrant_id", "data"]
      actions = ['remove_personal_information']
  
      def remove_personal_information(modeladmin, request, queryset):
          for q in queryset.iterator():
              remove_personally_identifiable_fields.delay(str(q.pk))
  
  
  class SubscriptionRequestAdmin(admin.ModelAdmin):
      list_display = [
          "id", "identity", "messageset", "next_sequence_number", "lang",
          "schedule", "created_at", "updated_at"]
      list_filter = ["messageset", "created_at"]
      search_fields = ["identity"]
  
  
  admin.site.register(Source)
  admin.site.register(Registration, RegistrationAdmin)
  admin.site.register(SubscriptionRequest, SubscriptionRequestAdmin)
  
subject: Add admin action for removing personal information