System.setProperty(Constants.FESS_CONFIG_PREFIX + testKey, newValue);

            // Get value again - in real FessConfigImpl it would be cached,
            // but our test implementation always checks system properties
            String value2 = fessConfig.get(testKey);
            // In our test implementation, it will pick up the new value
            assertEquals(newValue, value2);
        } finally {

            int start = dstIndex;
            dstIndex += writeHeaderWireFormat(dst, dstIndex);
            dstIndex += writeBytesWireFormat(dst, dstIndex);

            // Set the length field that will be checked by ServerMessageBlock2Request.encode()
            int calculatedLength = testEncodedLength;
            setLength(calculatedLength);

<img src="/img/python-types/image03.png">

## More motivation { #more-motivation }

Check this function, it already has type hints:

{* ../../docs_src/python_types/tutorial003.py hl[1] *}

Because the editor knows the types of the variables, you don't only get completion, you also get error checks:

<img src="/img/python-types/image04.png">

	// HTTP request for testing when `objectLayer` is set to `nil`.
	// There is no need to use an existing bucket and valid input for creating the request
	// since the `objectLayer==nil`  check is performed before any other checks inside the handlers.
	// The only aim is to generate an HTTP request in a way that the relevant/registered end point is evoked/called.
	nilBucket := "dummy-bucket"

  @SuppressWarnings("CatchingUnchecked") // sneaky checked exception
  public final boolean trySetAccessible() {
    // We can't call accessibleObject.trySetAccessible since that was added in Java 9 and this code
    // should work on Java 8. So we emulate it this way.
    try {
      accessibleObject.setAccessible(true);
      return true;
    } catch (Exception e) { // sneaky checked exception
      return false;
    }
  }

      if (node.previousSibling == null) {
        // requireNonNull is safe because we checked that not *both* siblings were null.
        keyList.head = requireNonNull(node.nextSibling);
      } else {
        node.previousSibling.nextSibling = node.nextSibling;
      }

      if (node.nextSibling == null) {
        // requireNonNull is safe because we checked that not *both* siblings were null.

          <item index="10" class="java.lang.String" itemvalue="org.checkerframework.checker.nullness.compatqual.NullableDecl" />
          <item index="11" class="java.lang.String" itemvalue="org.checkerframework.checker.nullness.compatqual.NullableType" />
          <item index="12" class="java.lang.String" itemvalue="org.checkerframework.checker.nullness.qual.Nullable" />

     * <p><b>Note:</b> in general, code should assume that the string form returned by {@code
     * ToStringHelper} for a given object may change. In particular, the list of types which are
     * checked for emptiness is subject to change. We currently check {@code CharSequence}s, {@code
     * Collection}s, {@code Map}s, optionals (including Guava's), and arrays.
     *
     * @since 33.4.0
     */
    @CanIgnoreReturnValue

  /**
   * A boolean condition for which a thread may wait. A {@code Guard} is associated with a single
   * {@code Monitor}. The monitor may check the guard at arbitrary times from any thread occupying
   * the monitor, so code should not be written to rely on how often a guard might or might not be
   * checked.
   *
   * <p>If a {@code Guard} is passed into any method of a {@code Monitor} other than the one it is

FastAPI will use this `response_model` to do all the data documentation, validation, etc. and also to **convert and filter the output data** to its type declaration.

/// tip

If you have strict type checks in your editor, mypy, etc, you can declare the function return type as `Any`.