old_contents: class Test{{ cookiecutter.repo_name|capitalize }}(TestCase):
      """Tests for `{{ cookiecutter.repo_name }}` module."""
  
      def setUp(self):
          super(Test{{ cookiecutter.repo_name|capitalize }}, self).setUp()
  
new_contents: from testtools import TestCase
  
  
  class Test{{ cookiecutter.repo_name|capitalize }}(TestCase):
      """Tests for `{{ cookiecutter.repo_name }}` module."""
  
      def setUp(self):
          super(Test{{ cookiecutter.repo_name|capitalize }}, self).setUp()
  
subject: Add TestTools import