code: def configure(self, n_jobs=1, parallel=None, **backend_args):
      self.parallel = parallel
      n_parallel = self.effective_n_jobs(n_jobs)
      self.executor = concurrent.futures.ThreadPoolExecutor(n_parallel)
      return n_parallel
  
file_path: mars/mars/learn/contrib/joblib/backend.py
imports: import concurrent.futures
  from ....None import remote
  from ....session import get_default_session, new_session
label_desc: Use image node_id 3 for calling the MarsDistributedBackend obj's underlying member method code with example usage: obj.configure(n_jobs, parallel) and returns: n_parallel