code: def testDoesntOverfill(self):
      b = reservoir._ReservoirBucket(10)
      for i in range(1000):
          b.AddItem(i)
      self.assertEqual(len(b.Items()), 10)
      self.assertEqual(b._num_items_seen, 1000)
  
imports: import tensorflow
  from tensorboard.backend.event_processing import reservoir
label_desc: Use image node_id 3 for calling the ReservoirBucketTest obj's underlying member method code with example usage: obj.testDoesntOverfill() without return types