6. Here we are returning a dictionary that contains `items` which is a list of dataclasses.

    FastAPI is still capable of <abbr title="converting the data to a format that can be transmitted">serializing</abbr> the data to JSON.

7. Here the `response_model` is using a type annotation of a list of `Author` dataclasses.

    Again, you can combine `dataclasses` with standard type annotations.

import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.util.Collection;
import java.util.Map;
import org.jspecify.annotations.Nullable;

/**
 * Provides static methods for serializing collection classes.
 *
 * <p>This class assists the implementation of collection classes. Do not use this class to
 * serialize collections that are defined elsewhere.
 *
 * @author Jared Levy
 */
@GwtIncompatible

import java.io.ObjectOutputStream;
import java.util.Set;

import org.codelibs.core.exception.ClassNotFoundRuntimeException;
import org.codelibs.core.exception.IORuntimeException;

/**
 * Utility for serializing objects with security protections.
 * <p>
 * This utility provides object serialization and deserialization with built-in
 * security protections against deserialization attacks. By default, it uses an

  @J2ktIncompatible
  @GwtIncompatible // SerializableTester
  @SuppressWarnings("unchecked")
  public void ignore_testSerializationNoDuplication_regularImmutableMap() throws Exception {
    // Tests that serializing a map, its keySet, and values only writes the underlying data once.

    Object[] entries = new Object[2000];
    for (int i = 0; i < entries.length; i++) {
      entries[i] = i;
    }

    }
  }

  private static class QueueSupplier extends CountingSupplier<Queue<Integer>> {
    @Override
    /*
     * We need a Queue that implements equals() for the equality tests we perform after
     * reserializing the multimap.
     */
    @SuppressWarnings("JdkObsolete")
    public Queue<Integer> getImpl() {
      return new LinkedList<>();
    }

* ✨ Support Python internal description on Pydantic model's docstring. PR [#3032](https://github.com/tiangolo/fastapi/pull/3032) by [@Kludex](https://github.com/Kludex).
* ✨ Update `ORJSONResponse` to support non `str` keys and serializing Numpy arrays. PR [#3892](https://github.com/tiangolo/fastapi/pull/3892) by [@baby5](https://github.com/baby5).

### Fixes