I am having trouble running my FastAPI project. I execute the following command: uvicorn main:ia --port 8000 --reload, and when it starts running, it throws the following error:

I am trying to create a custom chain that would be served via my langserve API and would accept configurable fields via the per_req_config_modifier that helps out in parsing headers from the API request and passing them on to the custom runnable class. I have defined the class like this so far which worked when I was using my own OpenAI API key to test. However, to enable passing the key from the request headers would require me to pass the key via config modifier as defined below. I have modified the class like so: