code: def forward(ctx, op, group, tensor, *input_tensor_list):
      ctx.group = group
      input_tensor_list = tuple(
          t.contiguous() for t in input_tensor_list
      )
      dist.reduce_scatter(
          tensor, list(input_tensor_list), op=op, group=group
      )
      return tensor
  
imports: import torch
  import torch.distributed
  from torch.autograd import Function
label_desc: Use image node_id 1 for calling the _Reduce_Scatter obj's underlying member method code with example usage: obj.forward(ctx, op, group, tensor) and returns: tensor