Type Hints and Static Typing

Add type hints to my Python code:

```python
[PASTE YOUR CODE HERE]
```

Requirements:
1. Add type hints for all function parameters and returns
2. Use typing module for complex types
3. Handle Optional and Union types
4. Generic types for containers
5. TypeVar for generic functions
6. Protocol for structural subtyping
7. TypedDict for dictionary structures
8. Callable for function types
9. Literal for specific values
10. Final for constants

Also provide:
- mypy configuration recommendations
- Common type hint patterns
- Runtime type checking options
- Documentation of type choices