code: def test_cache_credentials_backward_compatibility():
      # From v0.6.3.
      creds = {"s3": {"client_kwargs": {}}}
      backend = {
          "type": "local",
          "cache_dir": "/foo/bar",
          "cache_credentials": creds,
      }
  
      _update_backend_cache_credentials(backend)
  
      assert backend == {
          "type": "local",
          "cache_dir": "/foo/bar",
          "credentials": {"cache": creds},
      }
  
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 13 for calling a global function with example usage: test_cache_credentials_backward_compatibility() without return types