"""
        Clears import errors for files that no longer exist.
        :param file_paths: list of paths to DAG definition files
        :param session: session for ORM operations
        """
        query = session.query(errors.ImportError)
        if file_paths:
            query = query.filter(~errors.ImportError.filename.in_(file_paths))
        query.delete(synchronize_session="fetch")
        session.commit()
    def _log_file_processing_stats(self, known_file_paths):
        """
        Print out stats about how files are getting processed.
        :param known_file_paths: a list of file paths that may contain Airflow
            DAG definitions
        :return: None
        """