code: def backward(ctx, output_grad):
      return output_grad, None
  
imports: from typing import Any, Tuple
  import torch
  import torch.distributed
  from torch import Tensor
  from torch.cuda.amp import custom_bwd, custom_fwd
  from colossalai.legacy.communication.collective import all_gather, all_reduce, reduce_scatter
  from colossalai.legacy.context.parallel_mode import ParallelMode
  from colossalai.legacy.core import global_context
  from colossalai.utils import get_current_device
label_desc: Use image node_id 2 for calling the _ReduceTensor2p5D obj's underlying member method code with example usage: obj.backward(ctx, output_grad) and returns: output_grad,  None