code: def __len__(self):
      if self.captions is not None:
          return len(self.captions.keys())
      else:
          return len(self.paths)
  
file_path: colossalai/examples/images/diffusion/ldm/data/teyvat.py
imports: import json
  from pathlib import Path
  from typing import Dict
  import torch
  from datasets import load_dataset
  from einops import rearrange
  from ldm.util import instantiate_from_config
  from omegaconf import DictConfig, ListConfig
  from PIL import Image
  from torch.utils.data import Dataset
  from torchvision import transforms
label_desc: Use image node_id 2 for calling the FolderData obj's underlying member method code with example usage: obj.__len__() and returns: len, len