frozenset not working as expected

[as24-asingla]

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Example

Here's a self-contained, minimal, reproducible, example with my use case:

from fastapi import FastAPI

app = FastAPI()


@app.get("/prices", name='Prices for stocks')
def get_prices(stocks: Optional[frozenset]):

    return 23

Description

I get an error 422 when run the query on /docs page itself.

{
  "detail": [
    {
      "loc": [
        "query",
        "stocks"
      ],
      "msg": "value is not a valid frozenset",
      "type": "type_error.frozenset"
    }
  ]
}
```
### Environment

* OS: macOS
* FastAPI Version: 0.63.0

To know the FastAPI version use:

```bash
python -c "import fastapi; print(fastapi.__version__)"
```

* Python version: 3.8.5

To know the Python version use:

```bash
python --version
```

[ycd]

Python version: 2.7.18 a typo or?

[as24-asingla]

Sorry, its 3.8.5. 2.7.18 was the version of my EC2 instance and not docker.

[juntatalor]

@as24-asingla Hi! frozenset was not processed as a sequence (but set did). I suggest a solution in #2938

[theo-brown]

Hi, I've got this issue as well. Looks like #2938 hasn't been merged.

[tiangolo]

Hey there! Thanks for the discussion. This was solved by @juntatalor in #2938 🎉

It will be available in the next version, released in a couple of hours, FastAPI 0.81.0. 🚀

[github-actions]

Assuming the original need was handled, this will be automatically closed now. But feel free to add more comments or create new issues or PRs.

[kannanwisen]

@app.post("/FrozenSet")
def frozen_set(param1: FrozenSet[str] = Body(default=None)):
    print(param1, type(param1))
    return param1

If I pass like this, i get the below error.

If i pass like below, it works.

[kannanwisen]

Even same for bytes data type