DEV: use temp URL for sample

docs/develop/python/message-passing.mdx

@@ -39,7 +39,7 @@ See [Workflow message-passing](/encyclopedia/workflow-message-passing#sending-qu
 ## Writing Query, Signal, and Update handlers
 
 Here is an example Workflow Definition featuring Query, Signal, and Update handlers, and an Update validator.
-You can view this as a runnable sample at [hello/hello_message_passing.py](https://github.com/temporalio/samples-python/blob/main/hello/hello_message_passing.py).
+You can view this as a runnable sample at [hello/hello_message_passing.py](https://github.com/temporalio/samples-python/blob/dan/dan/docs_message_passing.py).
 
 ```python
 import asyncio