code: def get_or_create_environment(self, repo: str, branch: str,
                                    git_repo: Repo, repo_path: Path) -> str:  # pragma: no cover
          
          raise NotImplementedError
docs: Abstract method which must be implemented in subclasses, which must return a str path to a Python executable
          which will be used to run the script.
  
          See :meth:`BaseBackend.run <arca.BaseBackend.run>` to see arguments description.