class_docstr: Abstract class for all nonautoregressive-based models
class_docstr_tok: ["Abstract","class","for","all","nonautoregressive-based","models"]
code: def initialize_output_tokens(self, *args, **kwargs):
      return NotImplementedError
  
imports: import math
  import torch
  from fairseq.models.transformer import TransformerDecoder, TransformerEncoder, TransformerModel
  from fairseq.modules.transformer_sentence_encoder import init_bert_params
label_desc: Use image node_id 10 for calling the FairseqNATModel obj's underlying member method code with example usage: obj.initialize_output_tokens() and returns: NotImplementedError