Update langgraph_agent.py

langgraph_agent.py

@@ -6,6 +6,7 @@ from langchain_huggingface import ChatHuggingFace, HuggingFaceEndpoint
 from langchain_community.tools.tavily_search import TavilySearchResults
 from langchain_community.document_loaders import WikipediaLoader, ArxivLoader
 from langchain_core.messages import SystemMessage, HumanMessage
+from langchain_google_genai import ChatGoogleGenerativeAI
 from langchain_core.tools import tool
 
 @tool