Dataclasses docs don't mention needing import for @dataclass decorator

https://docs.python.org/3/library/dataclasses.html

I think the import is implied in the example since the docs page is for dataclasses module but adding an explicit import to InventoryItem at the top won't hurt too.

We could change the example with 

```
from dataclasses import dataclass

@dataclass
class InventoryItem:
    ...
```

Because it's not specified in the documentation (header, that we need to
import dataclass from dataclasses).

+1 for a small update.

You are free to propose a PR.

Have a nice day,

>I think the import is implied in the example since the docs page is for
>dataclasses module but adding an explicit import to InventoryItem at
>the top won't hurt too.
Yep, but explicit is better than implicit.

I think adding "from dataclasses import dataclass" in the first example is fine.

There's a similar import in the sqlite3 documentation, just to pick one at random.

Ok, I suggest to add a "first issue" for the sprint days at PyCon US.

I can find some example in the docs that didn't `import the correct module` even in the first example. Should we add the `import` statement for all of them?

I won't discourage anyone from making such changes, but I don't think it's a real problem. I haven't seen that people are confused about needing to import the module being discussed in the documentation. I don't think there's any expectation that the code in the documentation is actually executable as-is. They're not doctests, after all.

I agreed most of the documents won't need the change, but some documents like https://docs.python.org/3/library/dataclasses.html#dataclasses.field didn't mention we have to run `from typing import List` and I guess most developers not familiar with this package. I suggest we should add the import statement for the uncommon package.

I definitely think any missing import from typing should be added.

I also don't think it's critical to make examples within a module's docs work like a doctest. Plus I discourage importing objects directly off of modules anyway and this would actually promote that.

I tried a couple of the examples from the docs and found the setup to be a little confusing
amd inconsistent. For example, the decorator line "@decorator" requires you to use

from dataclasses import dataclass

while the example line "mylist: List[int] = field(default_factory=list)" requires you to use these

import dataclasses
import typing

and must be modified to
mylist: typing.List[int] = dataclasses.field(default_factory=list)

The decorator line could be modified to be
@dataclasses.dataclass
and the from/import line could be eliminated. But that seems awkward.

So, what is are best practices for handling the imports needed by these examples?
And should the examples be updated to be consistent with a best practice set of imports?
Or am I not understanding how this code works?

Also, the intro section states "If any of the added methods already exist on the class, a TypeError will be raised."
This statement seems incorrect and contrdicts the parameter documentation that follows.

I agree that for the more confusing ones, it would be better to write out the import statement explicitly.

This should be closed. The PR has been merged and the doc is now up to date.

Thanks for noticing, Karl!

versions: + Python 3.8