I think `Union[SomeType, None]` is more explicit about what it means.

It's just about the words and names. But those words can affect how you and your teammates think about the code.

As an example, let's take this function:

```python
from typing import Optional


def say_hi(name: Optional[str]):
    print(f"Hey {name}!")
```

        // Null username should be handled gracefully
        assertTrue(rateLimiter.checkAttempt(null, "192.168.1.8"), "Null username should be allowed");

        // Should not affect IP limiting
        rateLimiter.recordFailure(null, "192.168.1.8");
        assertTrue(rateLimiter.checkAttempt("realuser", "192.168.1.8"), "Should still track IP");
    }

    @Test

    assertEquals(3, uniqueEntries.size());
  }

  // Wrapper of EnumMultiset factory methods, because we need to skip create(Class).
  // create(Enum1.class) is equal to create(Enum2.class) but testEquals() expects otherwise.
  // For the same reason, we need to skip create(Iterable, Class).
  private static class EnumMultisetFactory {
    @Keep // used reflectively by testEquals

    given a distinguishing version number. Except as provided in Section
    4.3, no one other than the license steward has the right to modify
    this License.

    4.2. Effect of New Versions.

    You may always continue to use, distribute or otherwise make the
    Covered Software available under the terms of the version of the

 * @param <V> the value type of the map to be tested.
 * @author George van den Driessche
 */
@GwtCompatible
@Ignore("test runners must not instantiate and run this directly, only via suites we build")
// @Ignore affects the Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.
@SuppressWarnings("JUnit4ClassUsedInJUnit3")
@NullMarked
public abstract class AbstractMapTester<K extends @Nullable Object, V extends @Nullable Object>

      }
    }

    /**
     * Adds {@code element} to the {@code ImmutableSet}. If the {@code ImmutableSet} already
     * contains {@code element}, then {@code add} has no effect (only the previously added element
     * is retained).
     *
     * @param element the element to add
     * @return this {@code Builder} object
     * @throws NullPointerException if {@code element} is null

Pendant le développement, j'ai également contribué à [**Starlette**](https://www.starlette.dev/), l'autre exigence clé.

## Développement { #development }

 *
 * @author Jesse Wilson
 * @author Louis Wasserman
 */
@GwtIncompatible
@Ignore("test runners must not instantiate and run this directly, only via suites we build")
// @Ignore affects the Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.
@SuppressWarnings("JUnit4ClassUsedInJUnit3")
public class NavigableSetNavigationTester<E> extends AbstractSetTester<E> {

 *
 * @author Chris Povirk
 */
@GwtCompatible
@Ignore("test runners must not instantiate and run this directly, only via suites we build")
// @Ignore affects the Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.
@SuppressWarnings("JUnit4ClassUsedInJUnit3")
public class CollectionRetainAllTester<E> extends AbstractCollectionTester<E> {

    public void validate(Settings settings, SettingsProblemCollector problems) {
        if (settings.isUsePluginRegistry()) {
            addViolation(problems, Severity.WARNING, "usePluginRegistry", null, "is deprecated and has no effect.");
        }

        List<String> pluginGroups = settings.getPluginGroups();

        if (pluginGroups != null) {
            for (int i = 0; i < pluginGroups.size(); i++) {