code: def __init__(self, max_features=None):
      self.max_features = max_features
      if self.max_features:
          patch_dim = math.ceil(math.sqrt(self.max_features))
          self.img_h = patch_dim
          self.img_w = patch_dim
  
imports: import math
  import os
  import pickle
  from typing import Any
  import lmdb
  import numpy
  import torch
  from mmf.utils.file_io import PathManager
label_desc: Use image node_id 1 to create a new CHWFeatureReader object  with example: obj = CHWFeatureReader(max_features)