* TypeVariableImpl}. Otherwise it throws {@link UnsupportedOperationException}; this should only
   * apply to {@code getAnnotatedBounds()}. This does mean that users on Java who obtain an instance
   * of {@code TypeVariable} from {@link TypeResolver#resolveType} will not be able to call {@code
   * getAnnotatedBounds()} on it, but that should hopefully be rare.
   *

//// tab | Python 3.10+

```Python
q: Annotated[str | None] = None
```

////

//// tab | Python 3.8+

```Python
q: Annotated[Union[str, None]] = None
```

////

Both of those versions mean the same thing, `q` is a parameter that can be a `str` or `None`, and by default, it is `None`.

Now let's jump to the fun stuff. 🎉

This was designed this way mainly to allow using the same objects "yielded" by dependencies inside of background tasks, because the exit code would be executed after the background tasks were finished.

Nevertheless, as this would mean waiting for the response to travel through the network while unnecessarily holding a resource in a dependency with yield (for example a database connection), this was changed in FastAPI 0.106.0.

/// tip

		if err != nil && err != io.EOF && err != io.ErrUnexpectedEOF {
			// If there is a disconnection before globalNetPerfMinDuration (we give a margin of error of 1 sec)
			// would mean the network is not stable. Logging here will help in debugging network issues.
			if time.Since(connectTime) < (globalNetPerfMinDuration - time.Second) {
				adminLogIf(ctx, err)
			}
		}
		if err != nil {

conjunction with the Program under their own license agreement, and (ii) are
not derivative works of the Program.

   "Contributor" means any person or entity that distributes the Program.

"Licensed Patents" mean patent claims licensable by a Contributor which are
necessarily infringed by the use or sale of its Contribution alone or when
combined with the Program.

   * TypeVariableImpl}. Otherwise it throws {@link UnsupportedOperationException}; this should only
   * apply to {@code getAnnotatedBounds()}. This does mean that users on Java who obtain an instance
   * of {@code TypeVariable} from {@link TypeResolver#resolveType} will not be able to call {@code
   * getAnnotatedBounds()} on it, but that should hopefully be rare.
   *

#### Rationale

- SSE-C requires application to remember the keys for all GET/PUT operations, any unfortunate loss of keys would automatically mean the objects cannot be accessed anymore.
- SSE-C is hardly adopted by most widely used applications, applications prefer server to manage the keys via SSE-KMS or SSE-S3.

browser("Browser")
proxy["Proxy on http://0.0.0.0:9999/api/v1/app"]
server["Server on http://127.0.0.1:8000/app"]

browser --> proxy
proxy --> server
```

/// tip

The IP `0.0.0.0` is commonly used to mean that the program listens on all the IPs available in that machine/server.

///

The docs UI would also need the OpenAPI schema to declare that this API `server` is located at `/api/v1` (behind the proxy). For example:

And then, again, you get all the editor support:

<img src="/img/python-types/image06.png">

Notice that this means "`one_person` is an **instance** of the class `Person`".

It doesn't mean "`one_person` is the **class** called `Person`".

## Pydantic models { #pydantic-models }

<a href="https://docs.pydantic.dev/" class="external-link" target="_blank">Pydantic</a> is a Python library to perform data validation.

      } catch (NoClassDefFoundError fromAggregateFutureStateFallbackAtomicHelperTest) {
        /*
         * AtomicReferenceFieldUpdaterAtomicHelper should always work on the JVM. (I mean, it
         * "should" always work on Android, too, but we know of a Samsung bug there :)) However, in
         * AggregateFutureStateFallbackAtomicHelperTest, we test what happens to AggregateFuture in