And Python has a special data type for sets of unique items, the `set`.

Then we can declare `tags` as a set of strings:

{* ../../docs_src/body_nested_models/tutorial003_py310.py hl[12] *}

With this, even if you receive a request with duplicate data, it will be converted to a set of unique items.

And whenever you output that data, even if the source had duplicates, it will be output as a set of unique items.

After you have tests, then you can upgrade the **FastAPI** version to a more recent one, and make sure that all your code is working correctly by running your tests.

If everything is working, or after you make the necessary changes, and all your tests are passing, then you can pin your `fastapi` to that new recent version.

## About Starlette { #about-starlette }

You shouldn't pin the version of `starlette`.

    /** Default response timeout in milliseconds */
    int DEFAULT_RESPONSE_TIMEOUT = 30000;
    /** Default socket timeout in milliseconds */
    int DEFAULT_SO_TIMEOUT = 35000;
    /** Default receive buffer size in bytes */
    int DEFAULT_RCV_BUF_SIZE = 60416;
    /** Default send buffer size in bytes */
    int DEFAULT_SND_BUF_SIZE = 16644;
    /** Default session limit */
    int DEFAULT_SSN_LIMIT = 250;

# `UploadFile` class

You can define *path operation function* parameters to be of the type `UploadFile` to receive files from the request.

You can import it directly from `fastapi`:

```python
from fastapi import UploadFile
```

::: fastapi.UploadFile
    options:
        members:
            - file
            - filename
            - size
            - headers
            - content_type
            - read

## Query parameter list / multiple values { #query-parameter-list-multiple-values }

When you define a query parameter explicitly with `Query` you can also declare it to receive a list of values, or said in another way, to receive multiple values.

For example, to declare a query parameter `q` that can appear multiple times in the URL, you can write:

description: Suggest an idea for this project
labels: [ "a:feature", "to-triage" ]
assignees: [ ]
body:
  - type: markdown
    attributes:
      value: |
        Please follow the instructions below.
        We receive dozens of issues every week, so to stay productive, we will close issues that don't provide enough information.

        Please open Android-related issues on [the Android Issue Tracker](https://source.android.com/source/report-bugs)

        original_route_handler = super().get_route_handler()

        async def custom_route_handler(request: Request) -> Response:
            request = GzipRequest(request.scope, request.receive)
            return await original_route_handler(request)

        return custom_route_handler


app = FastAPI()
app.router.route_class = GzipRoute


@app.post("/sum")

        original_route_handler = super().get_route_handler()

        async def custom_route_handler(request: Request) -> Response:
            request = GzipRequest(request.scope, request.receive)
            return await original_route_handler(request)

        return custom_route_handler


app = FastAPI()
app.router.route_class = GzipRoute


@app.post("/sum")

        original_route_handler = super().get_route_handler()

        async def custom_route_handler(request: Request) -> Response:
            request = GzipRequest(request.scope, request.receive)
            return await original_route_handler(request)

        return custom_route_handler


app = FastAPI()
app.router.route_class = GzipRoute


@app.post("/sum")

            - query_params
            - path_params
            - cookies
            - client
            - state
            - url_for
            - client_state
            - application_state
            - receive
            - send
            - accept
            - receive_text
            - receive_bytes
            - receive_json
            - iter_text
            - iter_bytes
            - iter_json