# import typing

**[import typing](https://docs.python.org/3/library/typing.html)** is a Python import that provides type hints for static type checking. Use type annotations to document function signatures and catch bugs with tools like `mypy` before runtime.

## Example

```python
# Python
# description: type hints for functions and variables

from typing import List, Dict, Optional, Union

def process_names(names: List[str]) -> int:
    """Process a list of names and return count."""
    return len(names)

def find_user(user_id: int) -> Optional[Dict[str, str]]:
    """Find user by ID, return None if not found."""
    users = {1: {"name": "Alice"}, 2: {"name": "Bob"}}
    return users.get(user_id)

def convert(value: Union[int, str]) -> str:
    """Accept int or str, return string."""
    return str(value)

# Type hints for variables (Python 3.6+)
age: int = 30
names: List[str] = ["Alice", "Bob"]
```

## Common types

- `List[T]`: list of type T
- `Dict[K, V]`: dict with keys K, values V
- `Tuple[T, ...]`: tuple of type T
- `Set[T]`: set of type T
- `Optional[T]`: T or None (same as `Union[T, None]`)
- `Union[T1, T2]`: T1 or T2
- `Callable[[A, B], R]`: function taking A, B and returning R