[BREAKING] Python: Refactor workflow events to unified discriminated union pattern (#3690)

* Refactor events

* Merge main

* Fixes

* Cleanup

* Update samples and tests

* Remove unused imports

* PR feedback

* Merge main. Add properties for events to help typing

* Formatting

* Cleanup

* use builtins.type to avoid shadowing by WorkflowEvent.type attribute

* Final improvements

python/samples/getting_started/workflows/_start-here/step1_executors_and_edges.py

@@ -140,7 +140,7 @@ class ExclamationAdder(Executor):
         super().__init__(id=id)
 
     @handler(input=str, output=str)
-    async def add_exclamation(self, message: str, ctx: WorkflowContext) -> None:
+    async def add_exclamation(self, message, ctx) -> None:  # type: ignore
         """Add exclamation marks to the input.
 
         Note: The input=str and output=str are explicitly specified on @handler,
@@ -149,7 +149,7 @@ class ExclamationAdder(Executor):
         on @handler take precedence.
         """
         result = f"{message}!!!"
-        await ctx.send_message(result)
+        await ctx.send_message(result)  # type: ignore
 
 
 async def main():

python/samples/getting_started/workflows/_start-here/step2_agents_in_a_workflow.py

@@ -57,7 +57,6 @@ async def main():
     # of `AgentResponse` from the agents in the workflow.
     outputs = cast(list[AgentResponse], outputs)
     for output in outputs:
-        # TODO: author_name should be available in AgentResponse
         print(f"{output.messages[0].author_name}: {output.text}\n")
 
     # Summarize the final run state (e.g., COMPLETED)
@@ -66,7 +65,7 @@ async def main():
     """
     writer: "Charge Ahead: Affordable Adventure Awaits!"
 
-    reviewer: - Consider emphasizing both affordability and fun in a more dynamic way. 
+    reviewer: - Consider emphasizing both affordability and fun in a more dynamic way.
     - Try using a catchy phrase that includes a play on words, like “Electrify Your Drive: Fun Meets Affordability!”
     - Ensure the slogan is succinct while capturing the essence of the car's unique selling proposition.
 

python/samples/getting_started/workflows/_start-here/step3_streaming.py

@@ -3,7 +3,6 @@
 import asyncio
 
 from agent_framework import AgentResponseUpdate, ChatMessage, WorkflowBuilder
-from agent_framework._workflows._events import WorkflowOutputEvent
 from agent_framework.azure import AzureOpenAIChatClient
 from azure.identity import AzureCliCredential
 
@@ -58,7 +57,7 @@ async def main():
     ):
         # The outputs of the workflow are whatever the agents produce. So the events are expected to
         # contain `AgentResponseUpdate` from the agents in the workflow.
-        if isinstance(event, WorkflowOutputEvent) and isinstance(event.data, AgentResponseUpdate):
+        if event.type == "output" and isinstance(event.data, AgentResponseUpdate):
             update = event.data
             author = update.author_name
             if author != last_author:

python/samples/getting_started/workflows/_start-here/step4_using_factories.py

@@ -8,7 +8,6 @@ from agent_framework import (
     Executor,
     WorkflowBuilder,
     WorkflowContext,
-    WorkflowOutputEvent,
     executor,
     handler,
 )
@@ -87,7 +86,7 @@ async def main():
     async for event in workflow.run("hello world", stream=True):
         # The outputs of the workflow are whatever the agents produce. So the events are expected to
         # contain `AgentResponseUpdate` from the agents in the workflow.
-        if isinstance(event, WorkflowOutputEvent) and isinstance(event.data, AgentResponseUpdate):
+        if event.type == "output" and isinstance(event.data, AgentResponseUpdate):
             update = event.data
             if first_update:
                 print(f"{update.author_name}: {update.text}", end="", flush=True)