code: def backward(ctx, g):
      x = ctx.saved_tensors[0]
      return g * torch.exp(x.clamp(max=15))
  
imports: import torch
  from torch.autograd import Function
  from torch.cuda.amp import custom_bwd, custom_fwd
label_desc: Use image node_id 2 for calling the _trunc_exp obj's underlying member method code with example usage: obj.backward(ctx, g) and returns: unknown