code: def layout(self):
      return self._layout
  
imports: import logging
  import torch
  from ..attention_cell import gen_self_attn_mask
  from .transformer import TransformerEncoderLayer
  from ..layers import get_activation, sequence_mask
  from ...utils.registry import Registry
  from ...models.bert import bert_cfg_reg
label_desc: Use image node_id 2 for calling the BertModel obj's underlying member method code with example usage: obj.layout() and returns: self