code: def forward(ctx, output_tensor, input_tensor, group):
      ctx.group = group
      dist._all_gather_base(
          output_tensor, input_tensor.contiguous(), group=group
      )
      return output_tensor
  
imports: import torch
  import torch.distributed
  from torch.autograd import Function
label_desc: Use image node_id 1 for calling the _AllGatherBase obj's underlying member method code with example usage: obj.forward(ctx, output_tensor, input_tensor, group) and returns: output_tensor