old_contents: from django.contrib import admin
  
  from students.models import Student, Settings, Newsletter
  
  
  @admin.register(Student)
  class StudentAdmin(admin.ModelAdmin):
      list_display = ['name', 'prename', 'tutor_group', 'want_exam']
      list_filter = ['want_exam', 'tutor_group']
      list_display_links = ['name', 'prename']
      search_fields = ['name', 'prename']
      readonly_fields = ('created_at', 'updated_at')
  
  
  @admin.register(Newsletter)
  class NewsletterAdmin(admin.ModelAdmin):
      list_display = ['active', 'name']
      list_filter = ['active']
      list_display_links = ['name']
  
  
  @admin.register(Settings)
  class SettingsAdmin(admin.ModelAdmin):
      list_display = ['student_registration_enabled']
  
new_contents: from django.contrib import admin
  
  from students.models import Student, Settings, Newsletter
  
  
  @admin.register(Student)
  class StudentAdmin(admin.ModelAdmin):
      list_display = ['name', 'prename', 'tutor_group', 'want_exam']
      list_filter = ['want_exam', 'tutor_group']
      list_display_links = ['name', 'prename']
      search_fields = ['name', 'prename']
      readonly_fields = ('created_at', 'updated_at')
      filter_horizontal = ['newsletters']
  
  @admin.register(Newsletter)
  class NewsletterAdmin(admin.ModelAdmin):
      list_display = ['active', 'name']
      list_filter = ['active']
      list_display_links = ['name']
  
  
  @admin.register(Settings)
  class SettingsAdmin(admin.ModelAdmin):
      list_display = ['student_registration_enabled']
  
subject: Use filter_horizontal for students newsletters on admin