code: def _initialize_partition(self):
      # In order to ensure the down pipeline share the same parameter
      # with the up pipeline, partition of down partition will be copied
      # from corresponding up stage
      pp_rank = self.pp_rank
      stage_num = self.actual_stage_num
      self.device
      if pp_rank < stage_num:
          super()._initialize_partition()
      else:
          # if it is down pipeline, create partition by origin method
          co_up_pp_worker_rref = self.pp_rank_to_worker_rref[
              pp_rank - stage_num
          ]
          # get the corresponding model state dict and wait for its init
          state_dict = (
              co_up_pp_worker_rref.rpc_sync().get_partition_state_dict()
          )
          super()._initialize_partition()
          self.module_partition.load_state_dict(state_dict)
  
      # init group for chimera in ppg
      ppg.get_chimera_all_reduce_group(pp_rank)
  
      # lock for step sync
      self.step_sync_lock = threading.Lock()
      self.step_sync_lock.acquire()
  
      self.have_grad_lock = threading.Lock()
      self.have_grad_lock.acquire()
  
imports: import threading
  from typing import Callable, Dict, List
  import torch
  from torch._C._distributed_rpc import PyRRef
  from torch.futures import Future
  from colossalai.legacy.pipeline.pipeline_process_group import ppg
  from colossalai.legacy.pipeline.rpc._pipeline_base import Phase, PipelineEngineBase, UniqueKey, WorkerBase, WorkItem
label_desc: Use image node_id 3 for calling the ChimeraWorker obj's underlying member method code with example usage: obj._initialize_partition() without return types