code: def decode(self, tokens, state):
      return self(tokens, state)[0][:, -1]
  
imports: import torch
  from torch import nn
  from torch.nn import functional
  from transformers.models.bart.configuration_bart import BartConfig
  from .modeling_bart import BartModel
  from ..utils.util import avg_token_embeddings, seq_to_mask, get_model_device
  from functools import partial
  from typing import Union
label_desc: Use image node_id 3 for calling the PromptBartDecoder obj's underlying member method code with example usage: obj.decode(tokens, state) and returns: self