Update app.py

app.py

@@ -9,6 +9,7 @@ from langchain_core.tools import tool
 from langchain_core.utils.function_calling import convert_to_openai_tool
 from langgraph.graph import StateGraph, END
 
+
 # Environment Setup
 os.environ['OPENAI_API_KEY'] = os.getenv("OPENAI_API_KEY")
 
@@ -28,6 +29,10 @@ class AgentState(TypedDict):
 
 graph = StateGraph(AgentState)
 
+# Define MessagesState
+class MessagesState(TypedDict):
+    messages: Annotated[Sequence[BaseMessage], operator.add]
+
 def invoke_model(state):
     question = state['messages'][-1]
     return {"messages": [model_with_tools.invoke(question)]}