Update app.py

app.py

@@ -9,21 +9,24 @@ from langgraph.graph import Graph, StateGraph
 from langgraph.prebuilt import ToolNode
 from tools import simple_search
 from huggingface_hub import InferenceClient
-
+from langgraph.graph import State
+from typing import Annotated
+from typing_extensions import TypedDict 
 print("trial")
 # (Keep Constants as is)
 # --- Constants ---
 DEFAULT_API_URL = "https://agents-course-unit4-scoring.hf.space"
 HF_TOKEN = os.getenv("HF_TOKEN")  # Make sure to set this environment variable
 
+
 class AgentState(TypedDict):
-    question: str                # Fixed across steps
-    current_step: str           # Mutable
-    tool_output: str            # Mutable
-    final_answer: str           # Mutable
-    history: List[Dict[str, str]]  # Merged across steps
-    needs_more_info: bool       # Mutable
-    search_query: str           # Mutable
+    question: Annotated[str, State.Immutable]
+    current_step: str
+    tool_output: str
+    final_answer: str
+    history: Annotated[List[Dict[str, str]], State.MergingList]
+    needs_more_info: bool
+    search_query: str
 
 class BasicAgent:
     def __init__(self):