code: def num_samples(self):
      if self.encoder_output is not None:
          return self.encoder_output.size(0)
      else:
          return None
  
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 4 for calling the PromptBartState obj's underlying member method code with example usage: obj.num_samples() and returns: self, None