code: def test_audio_feature_backward_compatibility():
      # From v0.5.3.
  
      audio_feature_preprocessing_config = {
          "name": "audio_feature",
          "type": "audio",
          "preprocessing": {
              "audio_file_length_limit_in_s": 7.5,
              "missing_value_strategy": BFILL,
              "in_memory": True,
              "padding_value": 0,
              "norm": None,
              "audio_feature": {
                  "type": "fbank",
                  "window_length_in_s": 0.04,
                  "window_shift_in_s": 0.02,
                  "num_fft_points": None,
                  "window_type": "hamming",
                  "num_filter_bands": 80,
              },
          },
      }
  
      global_preprocessing_config = {
          "audio": {
              "audio_file_length_limit_in_s": 7.5,
              "missing_value_strategy": BFILL,
              "in_memory": True,
              "padding_value": 0,
              "norm": None,
              "audio_feature": {
                  "type": "fbank",
                  "window_length_in_s": 0.04,
                  "window_shift_in_s": 0.02,
                  "num_fft_points": None,
                  "window_type": "hamming",
                  "num_filter_bands": 80,
              },
          },
      }
  
      _upgrade_feature(audio_feature_preprocessing_config)
      _upgrade_preprocessing_split(global_preprocessing_config)
  
      assert global_preprocessing_config == {
          "audio": {
              "audio_file_length_limit_in_s": 7.5,
              "missing_value_strategy": BFILL,
              "in_memory": True,
              "padding_value": 0,
              "norm": None,
              "type": "fbank",
              "window_length_in_s": 0.04,
              "window_shift_in_s": 0.02,
              "num_fft_points": None,
              "window_type": "hamming",
              "num_filter_bands": 80,
          }
      }
  
      assert audio_feature_preprocessing_config == {
          "name": "audio_feature",
          "type": "audio",
          "preprocessing": {
              "audio_file_length_limit_in_s": 7.5,
              "missing_value_strategy": BFILL,
              "in_memory": True,
              "padding_value": 0,
              "norm": None,
              "type": "fbank",
              "window_length_in_s": 0.04,
              "window_shift_in_s": 0.02,
              "num_fft_points": None,
              "window_type": "hamming",
              "num_filter_bands": 80,
          },
      }
  
imports: import copy
  import math
  from typing import Any, Dict
  import pytest
  from ludwig.constants import BATCH_SIZE, BFILL, CLASS_WEIGHTS, DEFAULTS, EVAL_BATCH_SIZE, EXECUTOR, HYPEROPT, INPUT_FEATURES, LEARNING_RATE_SCHEDULER, LOSS, NUMBER, OUTPUT_FEATURES, PREPROCESSING, SCHEDULER, SPLIT, TRAINER, TYPE
  from ludwig.schema.model_config import ModelConfig
  from ludwig.schema.trainer import ECDTrainerConfig
  from ludwig.utils.backward_compatibility import _update_backend_cache_credentials, _upgrade_encoder_decoder_params, _upgrade_feature, _upgrade_preprocessing_split, upgrade_config_dict_to_latest_version, upgrade_missing_value_strategy, upgrade_model_progress
  from ludwig.utils.trainer_utils import TrainerMetric
label_desc: Use image node_id 2 for calling a global function with example usage: test_audio_feature_backward_compatibility() without return types