new_contents: import factory
  
  from mailme.models import Mailbox
  from mailme.tests.factories.user import UserFactory
  
  
  class MailboxFactory(factory.DjangoModelFactory):
      user = factory.SubFactory(UserFactory)
      name = 'custom'
      provider = 'custom'
  
      class Meta:
          model = Mailbox
  
subject: Add mailbox factory