<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def close(self) -> None: """Kill the managed Spark session."""

        if self.session_id is not None:
            self.client.delete_session(self.session_id)
        self.client.close()