code: def _start_devcluster(self) -> None:
      try:
          if self.is_circleci_job:
              # Use the pre-installed determined master service when running the tests as part
              # of a CircleCI job.
              subprocess.run(
                  sh_split("sudo systemctl start determined-master")
              )
          else:
              # Use a local instance of the devcluster.
              master_config_file = os.getenv("MASTER_CONFIG_FILE")
              if not master_config_file:
                  raise Exception(
                      "MASTER_CONFIG_FILE is not set. Please set the MASTER_CONFIG_FILE to point "
                      "to the master config file you want to use. Use ./tools/slurmcluster.sh -s "
                      "<machine name> to create a new one."
                  )
              if not os.path.exists(master_config_file):
                  raise Exception(
                      f"Master config file {master_config_file} is missing. Please use "
                      "./tools/slurmcluster.sh -s <machine name> to create one."
                  )
              self.dc = subprocess.Popen(  # type: ignore
                  ["devcluster", "-c", master_config_file, "--oneshot"],
                  cwd="..",
              )
          time.sleep(30)
      except Exception as e:
          print(e)
          raise
  
imports: import os
  import subprocess
  import time
  from shlex import split
  from typing import Any, Iterator
  import pytest
  from tests import config
  from .abstract_cluster import Cluster
  from .utils import now_ts
label_desc: Use image node_id 6 for calling the ManagedSlurmCluster obj's underlying member method code with example usage: obj._start_devcluster() without return types