advanced patterns When Using Type Hints with Async Functions in Python 3.10
Hey everyone, I'm running into an issue that's driving me crazy... I'm working with unexpected behavior when trying to use type hints with async functions in Python 3.10. I have an async function that fetches data from an API and is supposed to return a list of dictionaries. However, when I use type hints to specify the return type, I get a type behavior during runtime. Here's a simplified version of my code: ```python from typing import List, Dict import httpx async def fetch_data() -> List[Dict[str, str]]: async with httpx.AsyncClient() as client: response = await client.get('https://api.example.com/data') return response.json() # Assuming this returns a list of dictionaries ``` When I run my code, I'm getting the following behavior: ``` TypeError: 'NoneType' object is not subscriptable ``` This suggests that `response.json()` might not be returning what I expect. To debug, I added print statements and confirmed that `response.json()` returns `None`, which leads me to believe that the API response might not be as expected or there's an scenario with type hinting. I've checked the API and it does return a valid JSON response. I've also tried removing the type hints, and the code executes without behavior, but I want to ensure I'm using them correctly. Is there a specific way to handle type hints with async functions in Python 3.10, especially when dealing with external API calls? I've also tried using `Optional` but it didn't resolve the scenario. Any insights would be greatly appreciated! My development environment is macOS.