old_contents: from django.contrib import admin
  
  from .models import Board, BoardCollaborator
  
  
  admin.site.register([Board, BoardCollaborator])
  
new_contents: from django.contrib import admin
  
  from .models import Board, BoardCollaborator
  
  
  class BoardAdmin(admin.ModelAdmin):
      list_display = ('name', 'account', 'created_by', 'is_shared', )
  
  
  class BoardCollaboratorAdmin(admin.ModelAdmin):
      list_display = ('board', 'user', 'invited_user', 'permission', )
  
  
  admin.site.register(Board, BoardAdmin)
  admin.site.register(BoardCollaborator, BoardCollaboratorAdmin)
  
subject: Use custom admin for Board and BoardCollaborator