Feature request: allow validating keys that aren't declared in types

Feature request: allow validating keys that aren't declared in types: a task in MiMo-V2.6-RL-harbor-code: MiMo-V2.6-RL Code (Harbor) (Harbor dataset). I'm using nopt to parse arguments for a CLI tool. I declare the keys I expect via the types map and pass an invalidHandler to react to bad input…