Use filters instead of string formatting

src/adk_firestore_sessionmanager/firestore_session_service.py

@@ -19,6 +19,7 @@ from google.adk.sessions.base_session_service import (
 from google.adk.sessions.session import Session
 from google.adk.sessions.state import State
 from google.cloud.firestore_v1.async_client import AsyncClient
+from google.cloud.firestore_v1.base_query import FieldFilter
 from google.cloud.firestore_v1.field_path import FieldPath
 from google.genai.types import Content, Part
 from typing_extensions import override
@@ -289,7 +290,7 @@ class FirestoreSessionService(BaseSessionService):
         events_ref = self._events_col(app_name, user_id, session_id)
         query = events_ref
         if config and config.after_timestamp:
-            query = query.where("timestamp", ">=", config.after_timestamp)
+            query = query.where(filter=FieldFilter("timestamp", ">=", config.after_timestamp))
         query = query.order_by("timestamp")
 
         event_docs = await query.get()
@@ -360,10 +361,10 @@ class FirestoreSessionService(BaseSessionService):
         self, *, app_name: str, user_id: Optional[str] = None
     ) -> ListSessionsResponse:
         query = self._db.collection(f"{self._prefix}_sessions").where(
-            "app_name", "==", app_name
+            filter=FieldFilter("app_name", "==", app_name)
         )
         if user_id is not None:
-            query = query.where("user_id", "==", user_id)
+            query = query.where(filter=FieldFilter("user_id", "==", user_id))
 
         docs = await query.get()
         if not docs: