code: def valid_step(self, model, samples):
      results = []
      # run_cfg = slf.cfg.run_cfg
      captions = model.generate(
          samples,
          use_nucleus_sampling=False,
          num_beams=self.num_beams,
          max_length=self.max_len,
          min_length=self.min_len,
          repetition_penalty=self.repetition_penalty,
          length_penalty=self.length_penalty,
          top_p=self.top_p,
          temperature=self.temperature,
      )
      img_ids = samples[self.sample_id_key]
      for caption, img_id in zip(captions, img_ids):
          # not all img_ids are ints
          img_id = (
              int(img_id) if is_convertible_to_int(img_id) else img_id
          )
          if (
              self.img_ids and img_id not in self.img_ids
          ):  # only include specified img_ids if specified
              continue
          results.append({"caption": caption, "image_id": img_id})
  
      return results
  
imports: import json
  import os
  import pandas
  from tqdm import tqdm
  from lavis.common.dist_utils import main_process, get_rank
  from lavis.common.registry import registry
  from lavis.tasks.base_task import BaseTask
  from lavis.common.utils import is_convertible_to_int, is_url, cache_url
  from pycocoevalcap.eval import COCOEvalCap
  from pycocotools.coco import COCO
  from torchvision.datasets.utils import download_url
label_desc: Use image node_id 4 for calling the CaptionTask obj's underlying member method code with example usage: obj.valid_step(model, samples) and returns: results