services: ignore yielded None values

CHANGELOG.md

@@ -26,6 +26,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixed
 
+- Fixed an issue in `AIService` that would cause a yielded `None` value to be
+  processed.
+
 - RTVI's `bot-ready` message is now sent when the RTVI pipeline is ready and
   a first participant joins.
 

src/pipecat/services/ai_services.py

@@ -75,10 +75,11 @@ class AIService(FrameProcessor):
 
     async def process_generator(self, generator: AsyncGenerator[Frame, None]):
         async for f in generator:
-            if isinstance(f, ErrorFrame):
-                await self.push_error(f)
-            else:
-                await self.push_frame(f)
+            if f:
+                if isinstance(f, ErrorFrame):
+                    await self.push_error(f)
+                else:
+                    await self.push_frame(f)
 
 
 class AsyncAIService(AsyncFrameProcessor):