def evaluate_report(report):
        """Iterate over validation errors."""
        if report["valid"]:
            return
        for warn in report["warnings"]:
            LOGGER.warning(warn)
        # We only ever test one table at a time.
        for err in report["tables"][0]["errors"]:
            LOGGER.error(err["message"])
        raise ValueError("Invalid data file. Please see errors above.")
Iterate over validation errors.