code: def backward(ctx, grad):
      return (
          _all_to_all_for_tablewise(
              grad,
              ctx.pg,
              ctx.gather_strides,
              ctx.scatter_strides,
              forward=False,
          ),
          None,
          None,
          None,
      )
  
imports: from typing import List, Optional, Union
  import torch
  import torch.distributed
  from colossalai.legacy.global_variables import tensor_parallel_env
  from colossalai.legacy.nn.layer.utils import divide
  from colossalai.legacy.tensor import ColoTensorSpec, ProcessGroup
  from colossalai.tensor import ColoTensor
label_desc: Use image node_id 2 for calling the _DualAllToAllForTablewise obj's underlying member method code with example usage: obj.backward(ctx, grad) and returns: _all_to_all_for_tablewise,  None,  None,  None