{* ../../docs_src/custom_response/tutorial004.py hl[7,21,23] *}

In this example, the function `generate_html_response()` already generates and returns a `Response` instead of returning the HTML in a `str`.

By returning the result of calling `generate_html_response()`, you are already returning a `Response` that will override the default **FastAPI** behavior.

              }
            },
            directExecutor()));
    thingToCancel[0] = serializer.submit(Callables.returning(null), directExecutor());
    results.add(thingToCancel[0]);
    // Enqueue more than enough tasks to force reentrancy.
    for (int i = 0; i < 5; i++) {
      results.add(serializer.submit(Callables.returning(null), directExecutor()));
    }

    manualExecutorTask[0].run();

FastAPI will use this return type to:

* **Validate** the returned data.
    * If the data is invalid (e.g. you are missing a field), it means that *your* app code is broken, not returning what it should, and it will return a server error instead of returning incorrect data. This way you and your clients can be certain that they will receive the data and the data shape expected.
* Add a **JSON Schema** for the response, in the OpenAPI *path operation*.

	}

	// mariadb with returning, values will be appended with id map
	if len(values) == beforeLen*2 {
		t.Skipf("This test case skipped, because the db supports returning")
	}

	for i := range values {
		v, ok := values[i]["id"]
		if !ok {
			t.Fatal("failed to create data from map with table, returning map has no primary key")
		}

		var result User

    class DecodingTests {

        @Test
        @DisplayName("Should decode value correctly")
        void testDecode() throws NdrException {
            // Given: NdrShort and mock returning specific value
            int decodedValue = 200;
            NdrShort ndrShort = new NdrShort(0);
            when(mockBuffer.dec_ndr_short()).thenReturn(decodedValue);

            // When: Decoding the value

        mockNotifications.add(fileNotifyInfo1);
        mockNotifications.add(fileNotifyInfo2);
        mockNotifications.add(fileNotifyInfo3);
    }

    /**
     * Test watch() method returning notifications
     */
    @Test
    void testWatch() throws CIFSException {
        // Setup mock behavior
        when(watchHandle.watch()).thenReturn(mockNotifications);

        // Execute

        }
    }

    @Nested
    @DisplayName("Interface Method Contract Tests")
    class InterfaceMethodContractTests {

        @Test
        @DisplayName("Should define getSID method returning SID")
        void shouldDefineMethods() {
            ACE ace = mock(ACE.class);
            SID mockSid = mock(SID.class);
            when(ace.getSID()).thenReturn(mockSid);

        }
    }

    @Nested
    @DisplayName("Configuration Access Tests")
    class ConfigurationAccessTest {

        @Test
        @DisplayName("Should provide getConfig method returning Configuration")
        void shouldProvideGetConfigMethod() {
            assertDoesNotThrow(() -> {
                java.lang.reflect.Method getConfigMethod = SmbSession.class.getMethod("getConfig");

      assertEquals(RESULT_VALUE, f.get());
    }
    {
      MockExecutor mock = new MockExecutor();
      TestExecutor testExecutor = new TestExecutor(mock);
      Callable<String> task = Callables.returning(RESULT_VALUE);
      Future<String> f = testExecutor.submit(task);
      mock.assertLastMethodCalled("submit");
      assertEquals(RESULT_VALUE, f.get());
    }
  }

   * Invokable<?, Person> factory = Invokable.of(getNameMethod).returning(Person.class);
   * }
   */
  public final <R1 extends R> Invokable<T, R1> returning(Class<R1> returnType) {
    return returning(TypeToken.of(returnType));
  }

  /** Explicitly specifies the return type of this {@code Invokable}. */
  public final <R1 extends R> Invokable<T, R1> returning(TypeToken<R1> returnType) {