code: def _get_roi_from_mask(mask):
      cv2 = tfds.core.lazy_imports.cv2
      contours = _find_contours(
          mask, cv2.RETR_LIST, cv2.CHAIN_APPROX_SIMPLE
      )
      contours_areas = [cv2.contourArea(cont) for cont in contours]
      biggest_contour_idx = np.argmax(contours_areas)
      return contours[biggest_contour_idx]
  
imports: import csv
  import os
  import re
  from absl import logging
  import numpy
  from tensorflow_datasets.core.utils.lazy_imports_utils import tensorflow
  import tensorflow_datasets.public_api
label_desc: Use image node_id 8 for calling a global function with example usage: _get_roi_from_mask(mask) and returns: contours