LLM knowledge retrieval example

[skrawcz]

Reimplements https://github.com/openai/openai-cookbook/blob/main/examples/How_to_call_functions_for_knowledge_retrieval.ipynb

This example shows how you can use Hamilton to help create manageable code for creating and dealing
with LLM powered workflows.

Changes

• adds example

How I tested this

• ran this locally

Notes

• Haven't added it to the docs yet.
• Will squash merge this

Checklist

• PR has an informative and human-readable title (this will be pulled into the release notes)
• Changes are limited to a single goal (no scope creep)
• Code passed the pre-commit check & code is left cleaner/nicer than when first encountered.
• Any change in functionality is tested
• New functions are documented (with a description, list of inputs, and expected output)
• Placeholder code is flagged / future TODOs are captured in comments
• Project documentation has been updated if adding/changing functionality.