docs: def checked_run(cmd):
      """Prepare and run a subprocess cmd, checking for successful completion."""
      completed_process = run(cmd)
      if completed_process.returncode > 0:
          print("Command failed!  Hanging around in case someone needs a "
                "docker connection. (Ctrl-C to quit now)")
          time.sleep(300)
          raise RuntimeError
      return completed_process