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

And it will be annotated / documented accordingly too.

## Nested Models { #nested-models }

Each attribute of a Pydantic model has a type.

But that type can itself be another Pydantic model.

To declare a query parameter with a type of `list`, like in the example above, you need to explicitly use `Query`, otherwise it would be interpreted as a request body.

///

The interactive API docs will update accordingly, to allow multiple values:

<img src="/img/tutorial/query-params-str-validations/image02.png">

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

### API Change

- **ACTION REQUIRED** for custom scheduler plugin developers:
  `PodEligibleToPreemptOthers` in the `preemption` interface now includes `ctx` in the parameters.
  Please update your plugins' implementation accordingly. ([#126465](https://github.com/kubernetes/kubernetes/pull/126465), [@googs1025](https://github.com/googs1025)) [SIG Scheduling]

import java.io.ObjectOutputStream;
import java.util.LinkedHashMap;
import org.jspecify.annotations.Nullable;

/**
 * A {@code Multiset} implementation with predictable iteration order. Its iterator orders elements
 * according to when the first occurrence of the element was added. When the multiset contains
 * multiple instances of an element, those instances are consecutive in the iteration order. If all

import java.util.ConcurrentModificationException;
import java.util.Iterator;
import java.util.NoSuchElementException;
import org.jspecify.annotations.Nullable;

/**
 * A multiset which maintains the ordering of its elements, according to either their natural order
 * or an explicit {@link Comparator}. In all cases, this implementation uses {@link
 * Comparable#compareTo} or {@link Comparator#compare} instead of {@link Object#equals} to determine

import java.util.Iterator;
import java.util.NoSuchElementException;
import java.util.function.ObjIntConsumer;
import org.jspecify.annotations.Nullable;

/**
 * A multiset which maintains the ordering of its elements, according to either their natural order
 * or an explicit {@link Comparator}. In all cases, this implementation uses {@link
 * Comparable#compareTo} or {@link Comparator#compare} instead of {@link Object#equals} to determine

    to go about it.
2.  All contributions must be licensed Apache 2.0 and all files must have a copy
    of the boilerplate license comment (can be copied from an existing file).
3.  Files should be formatted according to Google's [Java style guide][].
4.  Do your best to have a [well-formed commit message][] for the change.
5.  Pull requests typically do not need to modify the files under the `android`

            }
        }
        return null;
    }

    /**
     * Processes field configurations to handle field overwriting rules.
     * Creates a new data map with fields processed according to their configuration.
     *
     * @param dataMap the original data map to process
     * @param fieldConfigs the field configurations to apply
     * @return a new data map with configurations applied
     */

httpx.post(callback_url, json={"description": "Invoice paid", "paid": True})
```

But possibly the most important part of the callback is making sure that your API user (the external developer) implements the *external API* correctly, according to the data that *your API* is going to send in the request body of the callback, etc.

So, what we will do next is add the code to document how that *external API* should look like to receive the callback from *your API*.