assertThat(CharMatcher.none().negate()).isSameInstanceAs(CharMatcher.any());
    assertThat(CharMatcher.any().negate()).isSameInstanceAs(CharMatcher.none());

    assertThat(CharMatcher.any().and(WHATEVER)).isSameInstanceAs(WHATEVER);
    assertThat(CharMatcher.any().or(WHATEVER)).isSameInstanceAs(CharMatcher.any());

    assertThat(CharMatcher.none().and(WHATEVER)).isSameInstanceAs(CharMatcher.none());

    assertEquals(0, ms.count(Color.BLUE));
    assertEquals(1, ms.count(Color.YELLOW));
    assertEquals(2, ms.count(Color.RED));
  }

  public void testIllegalCreate() {
    Collection<Color> empty = EnumSet.noneOf(Color.class);
    assertThrows(IllegalArgumentException.class, () -> EnumMultiset.create(empty));
  }

  public void testCreateEmptyWithClass() {

    assertEquals(0, ms.count(Color.BLUE));
    assertEquals(1, ms.count(Color.YELLOW));
    assertEquals(2, ms.count(Color.RED));
  }

  public void testIllegalCreate() {
    Collection<Color> empty = EnumSet.noneOf(Color.class);
    assertThrows(IllegalArgumentException.class, () -> EnumMultiset.create(empty));
  }

  public void testCreateEmptyWithClass() {

    }

    @Override
    public CharMatcher negate() {
      return none();
    }
  }

  /** Implementation of {@link #none()}. */
  private static final class None extends NamedFastMatcher {

    static final CharMatcher INSTANCE = new None();

    private None() {
      super("CharMatcher.none()");
    }

    @Override
    public boolean matches(char c) {

    EnumSet<E> set = EnumSet.noneOf(elementType);
    Iterables.addAll(set, iterable);
    return set;
  }

  // HashSet

  /**
   * Creates a <i>mutable</i>, initially empty {@code HashSet} instance.
   *
   * <p><b>Note:</b> if mutability is not required, use {@link ImmutableSet#of()} instead. If {@code
   * E} is an {@link Enum} type, use {@link EnumSet#noneOf} instead. Otherwise, strongly consider

    EnumSet<E> set = EnumSet.noneOf(elementType);
    Iterables.addAll(set, iterable);
    return set;
  }

  // HashSet

  /**
   * Creates a <i>mutable</i>, initially empty {@code HashSet} instance.
   *
   * <p><b>Note:</b> if mutability is not required, use {@link ImmutableSet#of()} instead. If {@code
   * E} is an {@link Enum} type, use {@link EnumSet#noneOf} instead. Otherwise, strongly consider

    }

    @Override
    public CharMatcher negate() {
      return none();
    }
  }

  /** Implementation of {@link #none()}. */
  private static final class None extends NamedFastMatcher {

    static final CharMatcher INSTANCE = new None();

    private None() {
      super("CharMatcher.none()");
    }

    @Override
    public boolean matches(char c) {

```

`name` 매개변수는 기본값이 없기 때문에 여전히 필수입니다(선택적이 아님). 대신, `name`에는 `None`을 전달할 수 있습니다:

```Python
say_hi(name=None)  # 작동합니다. None은 유효합니다 🎉
```

좋은 소식은, 대부분의 경우 타입의 합집합을 정의할 때 그냥 `|`를 사용할 수 있다는 점입니다:

```python
def say_hi(name: str | None):
    print(f"Hey {name}!")
```

    type: SchemaType | list[SchemaType] | None = None
    enum: list[Any] | None = None
    const: Any | None = None
    multipleOf: float | None = Field(default=None, gt=0)
    maximum: float | None = None
    exclusiveMaximum: float | None = None
    minimum: float | None = None
    exclusiveMinimum: float | None = None
    maxLength: int | None = Field(default=None, ge=0)
    minLength: int | None = Field(default=None, ge=0)

        default_factory: Callable[[], Any] | None = _Unset,
        annotation: Any | None = None,
        alias: str | None = None,
        alias_priority: int | None = _Unset,
        validation_alias: str | AliasPath | AliasChoices | None = None,
        serialization_alias: str | None = None,
        title: str | None = None,
        description: str | None = None,
        gt: float | None = None,
        ge: float | None = None,