code: def merge_features(input_dir: str, split: str, layer: str):
      return ExtractedFeaturesLoader.load_features(
          input_dir, split, layer
      )
  
imports: import collections
  import collections.abc
  import logging
  import os
  import random
  import sys
  import tempfile
  import time
  from functools import partial, wraps
  from typing import Tuple
  import numpy
  import pkg_resources
  import torch
  import torch.multiprocessing
  from iopath.common.file_io import g_pathmgr
  from scipy.sparse import csr_matrix
  from vissl.utils.extract_features_utils import ExtractedFeaturesLoader
label_desc: Use image node_id 12 for calling a global function with example usage: merge_features(input_dir, split, layer) and returns: ExtractedFeaturesLoader