code: def test_tokendrop(self):
      tokendrop_cls = get_transforms_cls(["tokendrop"])["tokendrop"]
      opt = Namespace(seed=3434, tokendrop_temperature=0.1)
      tokendrop_transform = tokendrop_cls(opt)
      tokendrop_transform.warm_up()
      ex = {
          "src": ["Hello", ",", "world", "."],
          "tgt": ["Bonjour", "le", "monde", "."],
      }
      # Not apply token drop for not training example
      ex_after = tokendrop_transform.apply(
          copy.deepcopy(ex), is_train=False
      )
      self.assertEqual(ex_after, ex)
      # apply token drop for training example
      ex_after = tokendrop_transform.apply(
          copy.deepcopy(ex), is_train=True
      )
      self.assertNotEqual(ex_after, ex)
  
imports: import unittest
  import copy
  import yaml
  import math
  from argparse import Namespace
  from onmt.transforms import get_transforms_cls, get_specials, make_transforms, TransformPipe
  from onmt.transforms.bart import BARTNoising
label_desc: Use image node_id 1 for calling the TestSamplingTransform obj's underlying member method code with example usage: obj.test_tokendrop() without return types