code: def forward(ctx, group, tensor):
      ctx.group = group
      out_tensor_list = [
          torch.empty_like(tensor)
          for _ in range(dist.get_world_size(group=group))
      ]
  
      dist.all_gather(out_tensor_list, tensor.contiguous(), group=group)
      return tuple(out_tensor_list)
  
imports: import torch
  import torch.distributed
  from torch.autograd import Function
label_desc: Use image node_id 1 for calling the _AllGather obj's underlying member method code with example usage: obj.forward(ctx, group, tensor) and returns: tuple