code: def layout(self):
      return self._layout
  
imports: import os
  from typing import Tuple, Optional
  import mxnet
  from mxnet import use_np, np, npx
  from mxnet.gluon import HybridBlock, nn
  from .base import BACKBONE_REGISTRY
  from ..op import select_vectors_by_position
  from ..base import get_model_zoo_home_dir, get_repo_model_zoo_url, get_model_zoo_checksum_dir
  from ..layers import InitializerType, PositionwiseFFN, PositionalEmbedding, get_norm_layer, get_activation
  from ..initializer import TruncNorm
  from ..utils.config import CfgNode
  from ..utils.misc import load_checksum_stats, download
  from ..utils.registry import Registry
  from ..attention_cell import MultiHeadAttentionCell, gen_self_attn_mask
  from ..data.tokenizers import HuggingFaceWordPieceTokenizer
label_desc: Use image node_id 2 for calling the MobileBertModel obj's underlying member method code with example usage: obj.layout() and returns: self