class_docstr: `MS Coco Detection <https://cocodataset.org/>`_ Dataset.
  
  Args:
      root (string): Root directory where images are downloaded to.
      dataset (string): "train" or "val.
      size (tuple): (h, w)
code: def __len__(self):
      return len(self.ids)
  
imports: import os
  import time
  import json
  import copy
  import cv2
  import numpy
  import torch
  from torchmetrics.detection.mean_ap import MeanAveragePrecision
  import torchvision
  from pycocotools.coco import COCO
  from pycocotools.cocoeval import COCOeval
  from compression.api import DataLoader, Metric
label_desc: Use image node_id 4 for calling the MyDataLoader obj's underlying member method code with example usage: obj.__len__() and returns: len