docstr: Feature Reader class for reading features.
  
  Note: Deprecation: ndim and image_feature will be deprecated later
  and the format will be standardize using features from detectron.
  
  Parameters
  ----------
  ndim : int
      Number of expected dimensions in features
  depth_first : bool
      CHW vs HWC
  max_features : int
      Number of maximum bboxes to keep
  
  Returns
  -------
  type
      Description of returned object.
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code: def __init__(self, base_path, depth_first, max_features=None):
      """Feature Reader class for reading features.
  
      Note: Deprecation: ndim and image_feature will be deprecated later
      and the format will be standardize using features from detectron.
  
      Parameters
      ----------
      ndim : int
          Number of expected dimensions in features
      depth_first : bool
          CHW vs HWC
      max_features : int
          Number of maximum bboxes to keep
  
      Returns
      -------
      type
          Description of returned object.
  
      """
      self.base_path = base_path
      ndim = None
      self.feat_reader = None
      self.depth_first = depth_first
      self.max_features = max_features
      self.ndim = ndim
  
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 FeatureReader object  with example: obj = FeatureReader(base_path, depth_first, max_features)