I'm working on a project where I'm using Celery, and I've made some utility functions that build and return task signatures. There have been times when I've used these utility functions in places where I haven't actually imported the Celery task type. What's the best practice according to Python's PEP 8 for handling this? It feels a bit excessive to import a whole library just for a type hint, but I'd like to keep my type hints without resorting to a generic `-> Object`. Any advice?
4 Answers
You should check out Python's `TYPE_CHECKING`. It's designed for this scenario!
You can use it like this:
```python
from typing import TYPE_CHECKING
if TYPE_CHECKING:
from somelib import SomeType
```
And remember, libraries are cached globally in Python, so importing a library multiple times doesn't add runtime costs as long as you import it in the same way.
You can utilize `if TYPE_CHECKING:` to import your type hints.
```python
from typing import TYPE_CHECKING
if TYPE_CHECKING:
from somelib import SomeType
```
This approach allows you to import types only during type checking, and when you reference them, just wrap the type in quotes like this:
```python
def func(x: 'SomeType'):
```
This helps avoid unnecessary imports at runtime, which is nice since it keeps your code clean and efficient!
Definitely check the Python docs for `TYPE_CHECKING`. It lays out all the information you might need for type hints without the performance hit of an import. It’s a lifesaver for keeping your code clean!
I get where you're coming from, but why not just import the type directly? Like this:
```python
from somelib import SomeType
```
It's not too heavy if you're already importing the library in other parts of your code. Just keep in mind that importing can load a lot of code, especially if you're not using it in your function.
Related Questions
Set Wordpress Featured Image Using Javascript
How To Fix PHP Random Being The Same
Why no WebP Support with Wordpress
Replace Wordpress Cron With Linux Cron
Customize Yoast Canonical URL Programmatically
[Centos] Delete All Files And Folders That Contain a String