code: def test_crowded(self):
      result = eval_detection_coco(
          self.pred_bboxes,
          self.pred_labels,
          self.pred_scores,
          self.gt_bboxes,
          self.gt_labels,
          gt_crowdeds=[[True]],
      )
      # When the only ground truth is crowded, nothing is evaluated.
      # In that case, all the results are nan.
      self.assertTrue(
          np.isnan(result["map/iou=0.50:0.95/area=all/max_dets=100"])
      )
      self.assertTrue(
          np.isnan(result["map/iou=0.50/area=all/max_dets=100"])
      )
      self.assertTrue(
          np.isnan(result["map/iou=0.75/area=all/max_dets=100"])
      )
  
imports: import numpy
  import os
  from six.moves.urllib import request
  import unittest
  from chainer import testing
  from chainercv.evaluations import eval_detection_coco
label_desc: Use image node_id 2 for calling the TestEvalDetectionCOCOSingleClass obj's underlying member method code with example usage: obj.test_crowded() without return types