code: def test_padding_with_attention_mask(self):
      if self.tokenizer.pad_token is None:
          self.skipTest("No padding token.")
      if "attention_mask" not in self.tokenizer.model_input_names:
          self.skipTest("This model does not use attention mask.")
  
      features = [
          {
              "token_ids": [1, 2, 3, 4, 5, 6],
              "attention_mask": [1, 1, 1, 1, 1, 0],
          },
          {"token_ids": [1, 2, 3], "attention_mask": [1, 1, 0]},
      ]
      padded_features = self.tokenizer.pad(features)
      if self.tokenizer.padding_side == "right":
          self.assertListEqual(
              padded_features["attention_mask"],
              [[1, 1, 1, 1, 1, 0], [1, 1, 0, 0, 0, 0]],
          )
      else:
          self.assertListEqual(
              padded_features["attention_mask"],
              [[1, 1, 1, 1, 1, 0], [0, 0, 0, 1, 1, 0]],
          )
  
imports: import os
  import pickle
  import shutil
  import tempfile
  import unittest
  from transformers.feature_extraction_utils import BatchFeature
  from transformers.testing_utils import is_pretty_midi_available, is_torch_available, require_pretty_midi, require_torch
  from transformers.tokenization_utils import BatchEncoding
label_desc: Use image node_id 14 for calling the Pop2PianoTokenizerTest obj's underlying member method code with example usage: obj.test_padding_with_attention_mask() without return types