code: def get_pc_path(self, sample_key):
      return os.path.join(
          self.pc_root,
          sample_key,
          "{}_{}.npz".format(sample_key, self.npoints),
      )
  
imports: import os, sys
  from collections import OrderedDict
  import random
  from lavis.datasets.datasets.base_dataset import BaseDataset
  from lavis.common.utils import is_serializable
  from PIL import Image
  import numpy
  from tqdm import tqdm
  import json
  import torch
  import copy
label_desc: Use image node_id 4 for calling the ObjaverseCaptionDataset obj's underlying member method code with example usage: obj.get_pc_path(sample_key) and returns: os