Ensure all parameters and outputs are typed

[mihaeladuta]

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[mihaeladuta]

At the meeting on 2024/12/05 we discussed and agreed on a uniform strategy for cases when typing work comes across issues with default values (e.g. None) not suitable for use in code: define a private function to assign a suitable default other than None and seed this function with a error raise to start with.

@abhidg and @lotzma please review the above.