What are some examples of type hints in Python 3.10, especially for async functions?

What are some examples of type hints in Python 3.10, especially for async functions?

In Python 3.10, type hints can enhance code readability and help with static type checking. For async functions, you can use async def along with type hints. Here's a simple example:

from typing import List, Optional

async def fetch_data(url: str) -> Optional[List[str]]:
    # Simulate an async operation
    return ['data1', 'data2']

Can you explain the Optional type hint in this context?

Sure! The Optional type hint indicates that the return value can either be of the specified type or None. In the example, fetch_data can return a list of strings or None if the data fetching fails.

What about using type hints with async generators?

Great question! You can use async def with yield to create async generators. Here's an example:

from typing import AsyncGenerator

async def async_numbers() -> AsyncGenerator[int, None]:
    for i in range(5):
        yield i