chore: fix typescript halluzinations

[mvarendorff]

Description

Fixes an alleged TypeScript halluzination by shuffling around code a bit. TypeScript requires a specific order for overloads; type declarations first, the implementing function body after.

• [x] I have read and understand the CONTRIBUTING.md document in this repository.

Type of change

• [x] Chore (non-breaking change which does not add functionality)

Checklist:

• [ ] I have added tests that prove my fix is effective or that my feature works
• [x] Existing test suite passes locally with my changes
• [ ] I have made corresponding changes to the documentation