#type-checking

#type-checking

TypedDict now controls both key requiredness and whether extra keys are allowed, with Python 3.15 adding closed TypedDict behavior to restrict unknown keys.

TypeScript infers literal argument types causing compile-time errors for mismatched values; Python's mypy requires explicit annotations to report the same mismatches.

Lazy annotations in Python 3.14 defer evaluation of annotations to improve performance, fix forward reference issues, and support static type checking and runtime processing.