* {@code C}
   *
   * <ul>
   *   <li>All visible static methods are checked such that passing null for any parameter that's
   *       not annotated nullable (according to the rules of {@link NullPointerTester}) should throw
   *       {@link NullPointerException}.
   *   <li>If there is any visible constructor or visible static factory method declared by the

   * {@code C}
   *
   * <ul>
   *   <li>All visible static methods are checked such that passing null for any parameter that's
   *       not annotated nullable (according to the rules of {@link NullPointerTester}) should throw
   *       {@link NullPointerException}.
   *   <li>If there is any visible constructor or visible static factory method declared by the

### Refactors

* ♻️ Upgrade internal syntax to Python 3.9+ 🎉. PR [#14564](https://github.com/fastapi/fastapi/pull/14564) by [@tiangolo](https://github.com/tiangolo).

### Docs