def source(self, site, rule):
        with self.connection() as db:
            cursor = db.execute('SELECT source_files FROM contexts '
                                'WHERE site = ? AND rule = ? '
                                'ORDER BY id DESC;', (site, rule))
            result = cursor.fetchone()
            if result is None:
                return []
            return pickle.loads(str(result[0]))
dataset/ETHPy150Open willowtreeapps/tango-core/tango/shelf.py/SqliteConnector.source/original