code: def get_nested_backend(self):
      return DaskDistributedBackend(client=self.client), -1
  
imports: from __future__ import print_function, division, absolute_import
  import asyncio
  import concurrent.futures
  import contextlib
  import time
  from uuid import uuid4
  import weakref
  from .parallel import parallel_config
  from .parallel import AutoBatchingMixin, ParallelBackendBase
label_desc: Use image node_id 3 for calling the DaskDistributedBackend obj's underlying member method code with example usage: obj.get_nested_backend() and returns: DaskDistributedBackend,  unknown