def _create_connection(self):
        """ create a database connection to a SQLite database """
        conn = None
        try:
            conn = sqlite3.connect(self.db_file)
        except Error as e:
            logging.error("Error occurred while connecting to database: %s", e)
            return None

        if conn:
            self._create_table(conn)

        return conn
 create a database connection to a SQLite database 
src/aios/environment/workflow_env.py