code: def forward(ctx, logp, posterior, dim=-1):
      ctx.save_for_backward(posterior)
      ctx.dim = dim
      return torch.logsumexp(logp, dim=dim)
  
imports: import torch
label_desc: Use image node_id 1 for calling the LogSumExpMoE obj's underlying member method code with example usage: obj.forward(ctx, logp, posterior, dim) and returns: torch