* Collections2#transform} or {@link Iterables#transform}.
   *
   * <p><b>Note:</b> serializing the returned list is implemented by serializing {@code fromList},
   * its contents, and {@code function} -- <i>not</i> by serializing the transformed values. This
   * can lead to surprising behavior, so serializing the returned list is <b>not recommended</b>.

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.

  @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.

    Entry<Integer, Integer>[] entries = (Entry<Integer, Integer>[]) new Entry<?, ?>[1000];
    for (int i = 0; i < 1000; i++) {

  @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;
    }

* ✨ 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