app.py

from langchain_google_genai import ChatGoogleGenerativeAI
from dotenv import load_dotenv
import os

load_dotenv()
google_api_key = os.getenv("GEMINI_API_KEY")
model ="gemini-2.5-flash-lite"

def run_hello_langchain():
    """
    Instantiates a ChatGoogleGenerativeAI model.
    Invokes it with a simple prompt.
    Prints the model's response.
    """
    llm = ChatGoogleGenerativeAI(model=model, google_api_key=google_api_key)
    response = llm.invoke("explain RLHF in 2 lines!")
    print(response.content)

run_hello_langchain()