code: def register_mars_backend():
      register_parallel_backend("mars", MarsDistributedBackend)
  
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 1 for calling a global function with example usage: register_mars_backend() without return types