code: def _get_subtask_processor_cls(cls, subtask_processor_cls):
      if subtask_processor_cls is None:
          return SubtaskProcessor
      else:
          assert isinstance(subtask_processor_cls, str)
          module, class_name = subtask_processor_cls.rsplit(".", 1)
          return getattr(importlib.import_module(module), class_name)
  
file_path: mars/mars/services/subtask/worker/runner.py
imports: import asyncio
  import importlib
  import logging
  from typing import Dict, Optional, Type
  from ....None import oscar
  from ....lib.aio import alru_cache
  from ....typing import BandType
  from ...cluster import ClusterAPI
  from ..core import Subtask, SubtaskResult
  from ..errors import SlotOccupiedAlready
  from .processor import SubtaskProcessor, SubtaskProcessorActor
label_desc: Use image node_id 3 for calling the SubtaskRunnerActor obj's underlying member method code with example usage: obj._get_subtask_processor_cls(cls, subtask_processor_cls) and returns: SubtaskProcessor, getattr