code: def regressfile(filename):
      
      _storybook({"rewrite": False}).in_filename(filename).with_params(
          **{"python version": "2.7.14"}
      ).filter(
          lambda story: not story.info.get("fails_on_python_2")
      ).ordered_by_name().play()
  
      _storybook({"rewrite": False}).with_params(
          **{"python version": "3.7.0"}
      ).in_filename(filename).ordered_by_name().play()
docs: Run all stories in filename 'filename' in python 2 and 3.