クエリパラメータの宣言と同様に、モデル属性がデフォルト値をもつとき、必須な属性ではなくなります。それ以外は必須になります。オプショナルな属性にしたい場合は `None` を使用してください。

例えば、上記のモデルは以下の様なJSON「`オブジェクト`」(もしくはPythonの `dict` ) を宣言しています:

```JSON
{
    "name": "Foo",
    "description": "An optional description",
    "price": 45.2,
    "tax": 3.5
}
```

...`description` と `tax` はオプショナル (デフォルト値は `None`) なので、以下のJSON「`オブジェクト`」も有効です:

```JSON
{
    "name": "Foo",
    "price": 45.2

# For example:
#
#	make v1.2.3.zip
#	make v1.2.3.test
#
# and then if changes are needed, check them into master
# and run 'make v1.2.3.rm' and repeat.
#
# Note that once published a snapshot zip file should never
# be modified. We record the sha256 hashes of the zip files
# in fips140.sum, and the cmd/go/internal/fips140 test checks
# that the zips match.
#

     * the query term is converted to lowercase for case-insensitive matching.
     *
     * @param query the search term to find related queries for
     * @return an array of related query strings, or empty array if none found
     */
    public String[] getRelatedQueries(final String query) {
        final String key = ComponentUtil.getVirtualHostHelper().getVirtualHostKey();
        final Map<String, String[]> map = relatedQueryMap.get(key);

    }
    node = nodeIterator.next();
    successorIterator = graph.successors(node).iterator();
    return true;
  }

  /**
   * If the graph is directed, each ordered [source, target] pair will be visited once if there is
   * an edge connecting them.
   */
  private static final class Directed<N> extends EndpointPairIterator<N> {
    private Directed(BaseGraph<N> graph) {
      super(graph);
    }

    @Override

        // Verify the result
        assertEquals(len, result, "readDataWireFormat should return the length of data read.");

        // Verify that the receive method on the input stream was called exactly once
        verify(mockPipeIn, times(1)).receive(buffer, bufferIndex, len);
    }

    /**
     * Tests the toString method.
     */
    @Test
    void testToString() {

If one of your dependencies is declared multiple times for the same *path operation*, for example, multiple dependencies have a common sub-dependency, **FastAPI** will know to call that sub-dependency only once per request.

		kmsRouter.Methods(http.MethodGet).Path(version + "/key/status").HandlerFunc(gz(httpTraceAll(kmsAPI.KMSKeyStatusHandler)))
	}

	// If none of the routes match add default error handler routes
	kmsRouter.NotFoundHandler = httpTraceAll(errorResponseHandler)
	kmsRouter.MethodNotAllowedHandler = httpTraceAll(methodNotAllowedHandler("KMS"))

    }

    @Test
    void testSetURLStreamHandlerFactory_ThrowsIllegalStateExceptionOnSecondAttempt() {
        // This test ensures that attempting to set the URLStreamHandlerFactory more than once
        // throws an IllegalStateException as per the contract.
        URLStreamHandlerFactory mockFactory1 = mock(URLStreamHandlerFactory.class);
        URLStreamHandlerFactory mockFactory2 = mock(URLStreamHandlerFactory.class);

     */
    @Nonnull
    Optional<MojoExecution> getMojoExecution();

    /**
     * Gets the exception that caused the event (if any).
     *
     * @return the exception or {@code empty()} if none
     */
    Optional<Exception> getException();

     * If no specific handler is found, returns the wildcard handler.
     *
     * @param origin the origin to look up
     * @return the CORS handler for the origin, or null if none found
     */
    public CorsHandler get(final String origin) {
        final CorsHandler handler = handerMap.get(origin);
        if (handler != null) {
            return handler;
        }