code: def assert_instance_created(self, model_class, **kwargs):
          
          return _InstanceContext(
              self.assert_instance_does_not_exist,
              self.assert_instance_exists,
              model_class,
              **kwargs
          )
docs: Checks if a model instance was created in the database.
  
          For example::
  
          >>> with self.assert_instance_created(Article, slug='lorem-ipsum'):
          ...     Article.objects.create(slug='lorem-ipsum')