{!../../docs_src/python_types/tutorial009c.py!}
```

Tham số `name` được định nghĩa là `Optional[str]`, nhưng nó **không phải là tùy chọn**, bạn không thể gọi hàm mà không có tham số:

```Python
say_hi()  # Oh, no, this throws an error! 😱
```

Tham số `name` **vẫn được yêu cầu** (không phải là *tùy chọn*) vì nó không có giá trị mặc định. Trong khi đó, `name` chấp nhận `None` như là giá trị:

```Python

{!../../docs_src/python_types/tutorial009c.py!}
```

O paâmetro `name` é definido como `Optional[str]`, mas ele **não é opcional**, você não pode chamar a função sem o parâmetro:

```Python
say_hi()  # Oh, no, this throws an error! 😱
```

O parâmetro `name` **ainda é obrigatório** (não *opicional*) porque ele não possui um valor padrão. Mesmo assim, `name` aceita `None` como valor:

```Python

          int expected = (x < y) ? 1 : 0;
          int actual = LongMath.lessThanBranchFree(x, y);
          assertEquals(expected, actual);
        }
      }
    }
  }

  // Throws an ArithmeticException if "the simple implementation" of binomial coefficients overflows
  @GwtIncompatible // TODO
  private long simpleBinomial(int n, int k) {
    long accum = 1;
    for (int i = 0; i < k; i++) {

   * are inclusive). For example, to match any lowercase letter of the English alphabet, use {@code
   * CharMatcher.inRange('a', 'z')}.
   *
   * @throws IllegalArgumentException if {@code endInclusive < startInclusive}
   */
  public static CharMatcher inRange(final char startInclusive, final char endInclusive) {
    return new InRange(startInclusive, endInclusive);
  }

public class QueryHelperTest extends UnitFessTestCase {

    private QueryHelper queryHelper;

    private QueryFieldConfig queryFieldConfig;

    @Override
    public void setUp() throws Exception {
        super.setUp();
        queryHelper = new QueryHelper() {
            protected QueryParser getQueryParser() {
                QueryParser queryParser = new QueryParser();

    scheduling. In your debugger you will see new thread names and more use of daemon threads.

 *  Fix: Don't drop callbacks on unexpected exceptions. When an interceptor throws an unchecked
    exception the callback is now notified that the call was canceled. The exception is still sent
    to the uncaught exception handler for reporting and recovery.

  @SuppressWarnings("rawtypes")
  private Class<? extends Enum> enumType;

  private String[] sampleData;

  @BeforeExperiment
  void setUp() throws ClassNotFoundException {
    Preconditions.checkArgument(hitRate >= 0 && hitRate <= 1, "hitRate must be in the range [0,1]");

    enumType =

   *       into account
   *   <li>the appropriate truncation indicator may be locale-dependent
   *   <li>it is safe to use non-ASCII characters in the truncation indicator
   * </ul>
   *
   * @throws IllegalArgumentException if {@code maxLength} is less than the length of {@code
   *     truncationIndicator}
   * @since 16.0
   */

    assertThat(converter.reverse().convert(1e-6f)).isEqualTo("1.0E-6");
  }

  @J2ktIncompatible
  @GwtIncompatible // NullPointerTester
  public void testStringConverter_nullPointerTester() throws Exception {
    NullPointerTester tester = new NullPointerTester();
    tester.testAllPublicInstanceMethods(Floats.stringConverter());
  }

  @GwtIncompatible
  public void testTryParse_withNullNoGwt() {

    assertThat(converter.reverse().convert(0666)).isEqualTo("438");
  }

  @J2ktIncompatible
  @GwtIncompatible // NullPointerTester
  public void testStringConverter_nullPointerTester() throws Exception {
    NullPointerTester tester = new NullPointerTester();
    tester.testAllPublicInstanceMethods(Ints.stringConverter());
  }

  public void testTryParse() {
    tryParseAndAssertEquals(0, "0");