latest requirements

app.py

@@ -202,12 +202,12 @@ class BasicAgent:
         self.builder = StateGraph(state_schema=AgentState)
 
         # Define nodes: these do the work
-        self.builder.add_node("start", lambda state: state)
+        self.builder.add_node("START", lambda state: state)
         self.builder.add_node("assistant", self.assistant)
         self.builder.add_node("tools", self.tools_node)
 
         # Define edges: these determine how the control flow moves
-        self.builder.add_edge("start", "assistant")
+        self.builder.add_edge("START", "assistant")
         self.builder.add_edge("assistant", "tools")
         self.builder.add_edge("tools", "assistant")
         self.react_graph = self.builder.compile()
@@ -230,7 +230,7 @@ class BasicAgent:
         fixed_answer = "This is a default answer."
 
         await asyncio.sleep(60)
-        messages = self.react_graph.invoke({"messages": [f'Task id: {task_id}\n {question}']}, node="start")
+        messages = self.react_graph.invoke({"messages": [f'Task id: {task_id}\n {question}']}, node="START")
         return messages["messages"][-1].content if messages["messages"] else fixed_answer