Using Portkey in Langchain to call Gemini API

langchain-gemini.py

from langchain_openai import ChatOpenAI
from portkey_ai import createHeaders, PORTKEY_GATEWAY_URL

portkey_headers = createHeaders(
    api_key="YOUR_PORTKEY_API_KEY",
    config={
        "virtual_key":"YOUR_GOOGLE_AI_STUDIO_VIRTUAL_KEY",
        "override_params":{
            "model":"gemini-1.5-pro-latest"
        }
    }
)

llm = ChatOpenAI(
    api_key="xx", # Passing a dummy value here
    base_url=PORTKEY_GATEWAY_URL,
    default_headers=portkey_headers
)

llm.invoke("What is the meaning of life, universe and everything?")