code: def prepare_feat_extract_dict(self):
      return {
          "n_bars": self.n_bars,
          "sample_rate": self.sample_rate,
          "use_mel": self.use_mel,
          "padding_value": self.padding_value,
          "vocab_size_special": self.vocab_size_special,
          "vocab_size_note": self.vocab_size_note,
          "vocab_size_velocity": self.vocab_size_velocity,
          "vocab_size_time": self.vocab_size_time,
      }
  
imports: import os
  import tempfile
  import unittest
  import numpy
  from datasets import load_dataset
  from transformers.testing_utils import check_json_file_has_correct_format, require_essentia, require_librosa, require_scipy, require_tf, require_torch
  from transformers.utils.import_utils import is_essentia_available, is_librosa_available, is_scipy_available, is_torch_available
  from ...test_sequence_feature_extraction_common import SequenceFeatureExtractionTestMixin
label_desc: Use image node_id 2 for calling the Pop2PianoFeatureExtractionTester obj's underlying member method code with example usage: obj.prepare_feat_extract_dict() and returns: dict