code: def cds_identifier_validator(record, result):
      
  
      record_external_identifiers = get_value(record, 'external_system_identifiers', [])
      result_external_identifiers = get_value(result, '_source.external_system_identifiers', [])
  
      record_external_identifiers = {external_id["value"] for external_id in record_external_identifiers if external_id["schema"] == 'CDS'}
      result_external_identifiers = {external_id["value"] for external_id in result_external_identifiers if external_id["schema"] == 'CDS'}
  
      return bool(record_external_identifiers & result_external_identifiers)
docs: Ensure that the two records have the same CDS identifier.
  
      This is needed because the search is done only for
      ``external_system_identifiers.value``, which might cause false positives in
      case the matched record has an identifier with the same ``value`` but
      ``schema`` different from CDS.
  
      Args:
          record (dict): the given record we are trying to match with similar ones in INSPIRE.
          result (dict): possible match returned by the ES query that needs to be validated.
  
      Returns:
          bool: validation decision.