new_contents: from bullet_train import BulletTrain
  from mock import patch
  from django.test import TestCase
  
  from ..utils import flag_smith_has_feature
  
  
  class TestUtils(TestCase):
      def test_flag_smith_has_feature(self):
          with patch("bullet_train.BulletTrain.has_feature") as mock_function:
              flag_smith_has_feature("feature_key")
              mock_function.assert_called_with("feature_key")
          
  
subject: Add quick unit test for flag_smith_has_feature