code: def test_descendants(self):
      root = base.Trackable()
      leaf = base.Trackable()
      root._track_trackable(leaf, name="leaf")
      descendants = trackable_view.TrackableView(root).descendants()
      self.assertIs(2, len(descendants))
      self.assertIs(root, descendants[0])
      self.assertIs(leaf, descendants[1])
  
imports: from tensorflow.python.checkpoint import trackable_view
  from tensorflow.python.eager import test
  from tensorflow.python.trackable import base
label_desc: Use image node_id 2 for calling the TrackableViewTest obj's underlying member method code with example usage: obj.test_descendants() without return types