Track 13 · Lesson 11 of 12

Type hints and static checks

Document what functions accept and return with type hints, and let tools like mypy and ruff find bugs before the code runs.

You will be able to

• Annotate parameters and return values with built-in and generic types
• Use X | None for values that may be missing, and handle the None case
• Explain what a static type checker such as mypy does and does not catch
• Describe what a linter such as ruff checks and how teams use these tools alongside tests