Support using service impl instead of interface

Author: dandavison

temporalio/workflow.py

@@ -4,7 +4,6 @@
 
 import asyncio
 import contextvars
-import dataclasses
 import inspect
 import logging
 import threading
@@ -43,6 +42,7 @@
 )
 
 import nexusrpc
+import nexusrpc.handler
 from typing_extensions import (
     Concatenate,
     Literal,
@@ -5158,7 +5158,7 @@ def __init__(
     # TODO(dan): overloads: no-input, operation name, ret type
     async def start_operation(
         self,
-        operation: Union[nexusrpc.Operation[I, O], str],
+        operation: Union[nexusrpc.interface.Operation[I, O], str],
         input: I,
         *,
         schedule_to_close_timeout: Optional[timedelta] = None,
@@ -5178,7 +5178,11 @@ async def start_operation(
     # TODO(dan): overloads: no-input, operation name, ret type
     async def execute_operation(
         self,
-        operation: nexusrpc.Operation[I, O],
+        operation: Union[
+            nexusrpc.interface.Operation[I, O],
+            Callable[..., nexusrpc.handler.Operation[I, O]],
+            str,
+        ],
         input: I,
         *,
         schedule_to_close_timeout: Optional[timedelta] = None,