Update src/agent.py

Co-authored-by: Ben Cherry <ben@livekit.io>

src/agent.py

@@ -107,10 +107,9 @@ async def my_agent(ctx: JobContext):
     await session.start(
         agent=Assistant(),
         room=ctx.room,
-        room_options=room_io.RoomOptions(
+room_options=room_io.RoomOptions(
             audio_input=room_io.AudioInputOptions(
-                # For telephony applications, use `BVCTelephony` for best results
-                noise_cancellation=noise_cancellation.BVC(),
+                noise_cancellation=lambda params: noise_cancellation.BVCTelephony() if params.participant.kind == rtc.ParticipantKind.PARTICIPANT_KIND_SIP else noise_cancellation.BVC(),
             ),
         ),
     )