code: def then_no_model_exists(context, model_name, key, value):
      
      model = apps.get_model(model_name)
      args = {
          key: value
      }
      obj = model.objects.filter(**args)
      assert len(obj) == 0
docs: :type model_name: str
      :type key: str
      :type value: str
      :type context: behave.runner.Context