How do I use typing in Python?

How do I use typing in Python?

You can use the typing module in Python to specify the expected data types of function arguments and return values.

Can you give me an example of how to use it?

Sure! Here's a simple example:

from typing import List

def greet_all(names: List[str]) -> None:
    for name in names:
        print(f'Hello, {name}!')

What if I want to use multiple types for a parameter?

You can use Union from the typing module. For example:

from typing import Union

def process_data(data: Union[int, str]) -> None:
    print(data)

Is there a way to specify optional parameters?

Yes! You can use Optional to indicate that a parameter can be of a specific type or None:

from typing import Optional

def fetch_data(url: str, timeout: Optional[int] = None) -> None:
    pass