file_path: xformers/xformers/triton/layer_norm.py
imports: import logging
  from typing import Optional
  import torch
  import torch.nn
  import triton
  from torch.cuda.amp import custom_bwd, custom_fwd
  from xformers.triton.k_layer_norm import layer_norm_bwd_dwdb, layer_norm_bwd_dx_fused, layer_norm_fw
label_desc: Use image node_id 1 for calling the _LayerNorm obj's underlying member method code with example usage: obj.forward(ctx, x, weight, bias, eps) and returns: y