code: def merge(
      folders,
      output_folder,
      threads,
      override=True,
      postprocessing_file=None,
      store_npz=False,
  ):
      print("ensemble predict...")
      if postprocessing_file is not None:
          output_folder_post = os.path.join(
              output_folder, "postprocessed"
          )
          os.makedirs(output_folder_post, exist_ok=True)
      else:
          output_folder_post = None
      output_folder = os.path.join(output_folder, "no_postprocessed")
      os.makedirs(output_folder, exist_ok=True)
  
      patient_ids = []
      for folder in folders:
          patients = []
          for file in os.listdir(folder):
              if file.endswith(".npz"):
                  patients.append(file)
          patient_ids.append(patients)
      patient_ids = [i for j in patient_ids for i in j]
      patient_ids = [i[:-4] for i in patient_ids]
      patient_ids = np.unique(patient_ids)
  
      for f in folders:
          print([os.path.join(f, i + ".npz") for i in patient_ids])
          assert all(
              [
                  os.path.isfile(os.path.join(f, i + ".npz"))
                  for i in patient_ids
              ]
          ), ("Not all patient npz are available in " "all folders")
          assert all(
              [
                  os.path.isfile(os.path.join(f, i + ".pkl"))
                  for i in patient_ids
              ]
          ), ("Not all patient pkl are available in " "all folders")
  
      files = []
      property_files = []
      out_files = []
      for p in patient_ids:
          files.append([os.path.join(f, p + ".npz") for f in folders])
          property_files.append(
              [os.path.join(f, p + ".pkl") for f in folders]
          )
          out_files.append(os.path.join(output_folder, p + ".nii.gz"))
  
      p = Pool(threads)
      p.starmap(
          merge_files,
          zip(
              files,
              property_files,
              out_files,
              [override] * len(out_files),
              [store_npz] * len(out_files),
          ),
      )
      p.close()
      p.join()
  
      if postprocessing_file is not None:
          with open(postprocessing_file, "rb") as f:
              pp_info = json.load(f)
          if "min_valid_object_sizes" in pp_info.keys():
              min_valid_object_sizes = ast.literal_eval(
                  pp_info["min_valid_object_sizes"]
              )
          else:
              min_valid_object_sizes = None
          for_which_classes, min_valid_obj_size = (
              pp_info["for_which_classes"],
              min_valid_object_sizes,
          )
          print("Postprocessing...")
          p = Pool(threads)
          nii_files = [
              file
              for file in os.listdir(output_folder)
              if file.endswith(".nii.gz")
          ]
          input_files = [
              os.path.join(output_folder, i) for i in nii_files
          ]
          out_files = [
              os.path.join(output_folder_post, i) for i in nii_files
          ]
          results = p.starmap_async(
              load_remove_save,
              zip(
                  input_files,
                  out_files,
                  [for_which_classes] * len(input_files),
                  [min_valid_obj_size] * len(input_files),
              ),
          )
          res = results.get()
          p.close()
          p.join()
  
          shutil.copy(postprocessing_file, output_folder_post)
          print("Postprocessing Done!")
      print("Ensemble predict Done!")
  
file_path: PaddleSeg/contrib/MedicalSeg/nnunet/ensemble.py
imports: import argparse
  import os
  import sys
  import ast
  import json
  import numpy
  import pickle
  import shutil
  from copy import deepcopy
  from multiprocessing import Pool
  from itertools import combinations
  from nnunet.utils import save_segmentation_nifti_from_softmax, load_remove_save, aggregate_scores, determine_postprocessing
label_desc: Use image node_id 4 for calling a global function with example usage: merge(folders, output_folder, threads, override, postprocessing_file, store_npz) without return types