code: def forward(
      ctx, group, output, output_split_sizes, input_split_sizes, input
  ):
      ctx.group = group
      ctx.input_size = input.size()
      ctx.output_split_sizes = input_split_sizes
      ctx.input_split_sizes = output_split_sizes
      dist.all_to_all_single(
          output,
          input,
          output_split_sizes=output_split_sizes,
          input_split_sizes=input_split_sizes,
          group=group,
      )
      return output
  
imports: import torch
  import torch.distributed
  from torch.autograd import Function
  from torch.distributed import group, ReduceOp
label_desc: Use image node_id 1 for calling the _AlltoAllSingle obj's underlying member method code with example usage: obj.forward(ctx, group, output, output_split_sizes, input_split_sizes, input) and returns: output