class_docstr: Latent depth (https://arxiv.org/abs/2009.13102) implemented in
  TransformerDecoder.
class_docstr_tok: ["Latent","depth","(","https",":","\/\/arxiv.org\/abs\/2009.13102",")","implemented","in","TransformerDecoder","."]
code: def set_lang_idx(self, lang_idx):
      self.lang_idx = lang_idx
  
imports: from typing import Any, Dict, Optional
  import torch.nn
  from fairseq.models.fairseq_encoder import EncoderOut
  from fairseq.models.transformer import TransformerDecoder, TransformerEncoder
  from fairseq.modules import TransformerDecoderLayer, TransformerEncoderLayer
  from torch import Tensor
  from ..modules.latent_layers import LayerSelect
label_desc: Use image node_id 2 for calling the LatentTransformerDecoder obj's underlying member method code with example usage: obj.set_lang_idx(lang_idx) without return types