feat: Align run_live interface with run_async etc

PiperOrigin-RevId: 758289318

src/google/adk/runners.py

@@ -19,6 +19,7 @@ import logging
 import queue
 import threading
 from typing import AsyncGenerator, Generator, Optional
+import warnings
 
 from deprecated import deprecated
 from google.genai import types
@@ -244,25 +245,52 @@ class Runner:
   async def run_live(
       self,
       *,
-      session: Session,
+      user_id: Optional[str] = None,
+      session_id: Optional[str] = None,
       live_request_queue: LiveRequestQueue,
       run_config: RunConfig = RunConfig(),
+      session: Optional[Session] = None,
   ) -> AsyncGenerator[Event, None]:
     """Runs the agent in live mode (experimental feature).
 
     Args:
-        session: The session to use.
+        session: The session to use. This parameter is deprecated, please use
+          `user_id` and `session_id` instead.
+        user_id: The user ID for the session. Required if `session` is None.
+        session_id: The session ID for the session. Required if `session` is
+          None.
         live_request_queue: The queue for live requests.
         run_config: The run config for the agent.
 
     Yields:
-        The events generated by the agent.
+        AsyncGenerator[Event, None]: An asynchronous generator that yields
+        `Event`
+        objects as they are produced by the agent during its live execution.
 
     .. warning::
         This feature is **experimental** and its API or behavior may change
         in future releases.
+
+    .. note::
+        Either `session` or both `user_id` and `session_id` must be provided.
     """
-    # TODO: right now, only works for a single audio agent without FC.
+    if session is None and (user_id is None or session_id is None):
+      raise ValueError(
+          'Either session or user_id and session_id must be provided.'
+      )
+    if session is not None:
+      warnings.warn(
+          'The `session` parameter is deprecated. Please use `user_id` and'
+          ' `session_id` instead.',
+          DeprecationWarning,
+          stacklevel=2,
+      )
+    if not session:
+      session = self.session_service.get_session(
+          app_name=self.app_name, user_id=user_id, session_id=session_id
+      )
+      if not session:
+        raise ValueError(f'Session not found: {session_id}')
     invocation_context = self._new_invocation_context_for_live(
         session,
         live_request_queue=live_request_queue,