class_docstr: Dataset class for the COCO dataset that maps classes to PASCAL VOC classes
  
  Args:
      opts: command-line arguments
class_docstr_tok: ["Dataset","class","for","the","COCO","dataset","that","maps","classes","to","PASCAL","VOC","classes","Args",":","opts",":","command-line","arguments"]
code: def __len__(self) -> int:
      return len(self.ids)
  
file_path: ml-cvnets/data/datasets/segmentation/coco_segmentation.py
imports: import argparse
  import os
  from typing import List, Mapping, Optional, Tuple, Union
  import numpy
  from pycocotools import mask
  from pycocotools.coco import COCO
  from torch import Tensor
  from data.datasets import DATASET_REGISTRY
  from data.datasets.segmentation.base_segmentation import BaseImageSegmentationDataset
label_desc: Use image node_id 4 for calling the COCOSegmentationDataset obj's underlying member method code with example usage: obj.__len__() and returns: len