code: def _validate_results(results: Iterable[AttackResults]):
      for attack_results in results:
          if (
              not attack_results
              or not attack_results.privacy_report_metadata
          ):
              raise ValueError("Privacy metadata is not defined.")
          if attack_results.privacy_report_metadata.epoch_num is None:
              raise ValueError("epoch_num in metadata is not defined.")
  
file_path: privacy/tensorflow_privacy/privacy/privacy_tests/membership_inference_attack/privacy_report.py
imports: from typing import Iterable, Sequence
  import matplotlib.pyplot
  import pandas
  from tensorflow_privacy.privacy.privacy_tests.membership_inference_attack.data_structures import AttackResults
  from tensorflow_privacy.privacy.privacy_tests.membership_inference_attack.data_structures import AttackResultsCollection
  from tensorflow_privacy.privacy.privacy_tests.membership_inference_attack.data_structures import AttackResultsDFColumns
  from tensorflow_privacy.privacy.privacy_tests.membership_inference_attack.data_structures import ENTIRE_DATASET_SLICE_STR
  from tensorflow_privacy.privacy.privacy_tests.membership_inference_attack.data_structures import PrivacyMetric
label_desc: Use image node_id 5 for calling a global function with example usage: _validate_results(results) without return types