* @param client The OpenSearch client.
     * @param settings The SuggestSettings instance.
     * @param readingConverter The ReadingConverter instance.
     * @param contentsReadingConverter The contents ReadingConverter instance.
     * @param normalizer The Normalizer instance.
     * @param analyzer The SuggestAnalyzer instance.
     * @param threadPool The ExecutorService for thread pooling.

  }

  Optional() {}

  /**
   * Returns {@code true} if this holder contains a (non-null) instance.
   *
   * <p><b>Comparison to {@code java.util.Optional}:</b> no differences.
   */
  public abstract boolean isPresent();

  /**
   * Returns the contained instance, which must be present. If the instance might be absent, use
   * {@link #or(Object)} or {@link #orNull} instead.
   *

      if (Serializable.class.isAssignableFrom(classToTest)) {
        try {
          Object instance = tester.instantiate(classToTest);
          if (instance != null) {
            if (isEqualsDefined(classToTest)) {
              SerializableTester.reserializeAndAssert(instance);
            } else {
              SerializableTester.reserialize(instance);
            }
          }
        } catch (Throwable e) {

        File tempFile = createTempFile("pomTest");
        FileModelSource instance = new FileModelSource(tempFile);

        assertFalse(instance.equals(null), "Expected " + instance + " to not equal " + null);
        assertFalse(instance.equals(new Object()));
        assertTrue(instance.equals(instance), "Expected " + instance + " to equal " + instance);
        assertTrue(instance.equals(new FileModelSource(tempFile)));
    }

    @Test

But we want to be able to parameterize that fixed content.

## A "callable" instance { #a-callable-instance }

In Python there's a way to make an instance of a class a "callable".

Not the class itself (which is already a callable), but an instance of that class.

To do that, we declare a method `__call__`:

{* ../../docs_src/dependencies/tutorial011_an_py310.py hl[12] *}

        dt_field: safe_datetime

    instance = MyDict(dt_field=safe_datetime.now())

    encoded_instance = jsonable_encoder(
        instance, custom_encoder={safe_datetime: lambda o: o.strftime("%H:%M:%S")}
    )
    assert encoded_instance["dt_field"] == instance["dt_field"].strftime("%H:%M:%S")

    encoded_instance = jsonable_encoder(
        instance, custom_encoder={datetime: lambda o: o.strftime("%H:%M:%S")}

    /**
     * Get an MD5 message digest instance.
     * @return MD5 digest instance
     */
    public static MessageDigest getMD5() {
        try {
            return MessageDigest.getInstance("MD5");
        } catch (final NoSuchAlgorithmException e) {
            throw new CIFSUnsupportedCryptoException(e);
        }
    }

    /**
     * Get a SHA-512 message digest instance.
     * @return SHA512 digest instance

                                instances.add(info);
                            }
                        }
                    }
                }
            }
        } catch (final Exception e) {
            logger.warn("Failed to get active instances.", e);
        }
        return instances;
    }

    /**
     * Checks whether the specified instance is currently active.
     *

     * @return this ExecJob instance for method chaining
     */
    public ExecJob timeout(final int timeout) {
        this.timeout = timeout;
        return this;
    }

    /**
     * Sets whether to use local Fesen instance.
     *
     * @param useLocalFesen true to use local Fesen, false otherwise
     * @return this ExecJob instance for method chaining
     */

   * this parameter is marked nullable, this method does nothing.
   *
   * @param instance the instance to invoke {@code method} on, or null if {@code method} is static
   */
  public void testMethodParameter(@Nullable Object instance, Method method, int paramIndex) {
    method.setAccessible(true);
    testParameter(instance, invokable(instance, method), paramIndex, method.getDeclaringClass());
  }

  /**