class_docstr: Gather the input from model parallel region and concatinate.
class_docstr_tok: ["Gather","the","input","from","model","parallel","region","and","concatinate","."]
code: def backward(ctx, grad_output):  # type: ignore
      return _split(grad_output)
  
imports: from typing import Any
  import torch
  from .initialize import get_model_parallel_group
  from .utils import split_tensor_along_last_dim
label_desc: Use image node_id 2 for calling the _GatherFromModelParallelRegion obj's underlying member method code with example usage: obj.backward(ctx, grad_output) and returns: _split