code: def aggregate_meta_info(exp_dir):
      files = [
          os.path.join(exp_dir, f)
          for f in os.listdir(exp_dir)
          if "meta_info" in f
      ]
      df = pd.DataFrame(columns=["path", "class_id", "pid"])
      for f in files:
          with open(f, "rb") as handle:
              df.loc[len(df)] = pickle.load(handle)
  
      df.to_pickle(os.path.join(exp_dir, "info_df.pickle"))
      print("aggregated meta info to df with length", len(df))
  
file_path: medicaldetectiontoolkit/experiments/toy_exp/generate_toys.py
imports: import os
  import numpy
  import pandas
  import pickle
  from multiprocessing import Pool
  import configs
label_desc: Use image node_id 3 for calling a global function with example usage: aggregate_meta_info(exp_dir) without return types