OpenAI key is needed even if Ollama specified.

[iplayfast]

Added this in the examples issue https://github.com/joaomdmoura/crewAI-examples/issues/2 I tried the stock analsys example, and it looked like it was working until it needed an OPEN_API key.

Also It expects a key to be in the environment for open ai, I feel it should only look for a key when it is actually going to use it.