import os
import time
import operator

from typing import TypedDict, List, Annotated
from langchain_openai import ChatOpenAI
from langgraph.graph import END, StateGraph
from langchain_core.prompts import ChatPromptTemplate, MessagesPlaceholder
from langchain_core.messages import HumanMessage

llm = ChatOpenAI(model="gpt-4o", temperature=0.1)