Fix mypy errors

Summary

Type definitions, a few asserts, str casts, and a lone exception for obviously wrong code.

Focus

Does this look plausible?

Test Environment

Pipelines should be sufficient

Check List for the Author

Please, prepare your MR for a review. Be sure to write a summary and a focus and create gitlab comments for the reviewer. They should guide the reviewer through the changes, explain your changes and also point out open questions. For further good practices have a look at our review guidelines

• All automated tests pass
• Reference related issues caosdb/customers/f-fit/management#85
• Up-to-date CHANGELOG.md (or not necessary)
• Up-to-date JSON schema (or not necessary)
• Appropriate user and developer documentation (or not necessary)
  • How do I use the software? Assume "stupid" users.
  • How do I develop or debug the software? Assume novice developers.
• Annotations in code (Gitlab comments)
  • Intent of new code
  • Problems with old code
  • Why this implementation?

Check List for the Reviewer

• I understand the intent of this MR
• All automated tests pass
• Up-to-date CHANGELOG.md (or not necessary)
• Appropriate user and developer documentation (or not necessary)
• The test environment setup works and the intended behavior is reproducible in the test environment
• In-code documentation and comments are up-to-date.
• Check: Are there specifications? Are they satisfied?

For further good practices have a look at our review guidelines.

assigned to @daniel

added 3 commits

• 5449a726 - WIP: Modernizing setup.
• c5a51e45 - Merge branch 'dev' into f-test-requirements
• 137ec2a6 - Merge branch 'f-test-requirements' into f-fix-mypy-errors

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added 1 commit

• 0fb754fa - MAINT: Enforcing mypy

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marked the checklist item All automated tests pass as completed

marked the checklist item Annotations in code (Gitlab comments) as completed

requested review from @florian

marked the checklist item I understand the intent of this MR as completed

marked the checklist item All automated tests pass as completed

added 1 commit

• 937ceb48 - DOC: Update changelog

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marked the checklist item Up-to-date CHANGELOG.md (or not necessary) as completed

marked the checklist item Appropriate user and developer documentation (or not necessary) as completed

resolved all threads

added 1 commit

• cb5c7db7 - FIX: Fixed undefined variable.

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marked the checklist item The test environment setup works and the intended behavior is reproducible in the test as completed

marked the checklist item In-code documentation and comments are up-to-date. as completed

enabled an automatic merge when all merge checks for cb5c7db7 pass

mentioned in commit 0e81a8e3

merged