private static final @Nullable String NE = null;

  private static <E extends @Nullable Object> Entry<E> entry(E element, int count) {
    return Multisets.immutableEntry(element, count);
  }

  private static <E extends @Nullable Object> Entry<E> control(E element, int count) {
    return HashMultiset.create(nCopies(count, element)).entrySet().iterator().next();
  }

  public void testToString() {

        this.scopes.add(scope);

        addScopeInternal(scope);
    }

    public Set<String> getScopes() {
        return scopes;
    }

    @Override
    public int hashCode() {
        int hash = 17;

        hash = hash * 31 + scopes.hashCode();

        return hash;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;

        super(null);
        this.node = node;
    }

    Xpp3DomNodePointer(NodePointer parent, XmlNode node) {
        super(parent);
        this.node = node;
    }

    @Override
    public int compareChildNodePointers(NodePointer pointer1, NodePointer pointer2) {
        XmlNode node1 = (XmlNode) pointer1.getBaseValue();
        XmlNode node2 = (XmlNode) pointer2.getBaseValue();
        if (node1 == node2) {

        // Create a stream that will cause an error during reading
        final InputStream errorStream = new InputStream() {
            @Override
            public int read() throws IOException {
                throw new IOException("Simulated read error");
            }
        };

        final String customEncoding = "ISO-8859-1";
        textExtractor.setEncoding(customEncoding);

}
```

当然，把一些参数定义为必选，为另一些参数设置默认值，再把其它参数定义为可选，这些操作都是可以的：

{* ../../docs_src/query_params/tutorial006_py310.py hl[8] *}

本例中有 3 个查询参数：

* `needy`，必选的 `str` 类型参数
* `skip`，默认值为 `0` 的 `int` 类型参数
* `limit`，可选的 `int` 类型参数

/// tip | 提示

还可以像在[路径参数](path-params.md#_8){.internal-link target=_blank} 中那样使用 `Enum`。

class ReviewNode(BaseModel):
    author: Author | None = None
    state: str


class Reviews(BaseModel):
    nodes: list[ReviewNode]


class PullRequestNode(BaseModel):
    number: int
    labels: Labels
    author: Author | None = None
    title: str
    createdAt: datetime
    lastEditedAt: datetime | None = None
    updatedAt: datetime | None = None
    state: str
    reviews: Reviews

		if err != nil {
			return nil, err
		}
		return sql.FromFloat(v), nil
	case simdjson.TypeInt:
		v, err := iter.Int()
		if err != nil {
			return nil, err
		}
		return sql.FromInt(v), nil
	case simdjson.TypeUint:
		v, err := iter.Int()
		if err != nil {
			// Can't fit into int, convert to float.
			v, err := iter.Float()
			return sql.FromFloat(v), err
		}
		return sql.FromInt(v), nil

        Comparable[] c = new Comparable[versions.length];
        for (int i = 0; i < versions.length; i++) {
            c[i] = newComparable(versions[i]);
        }

        for (int i = 1; i < versions.length; i++) {
            Comparable low = c[i - 1];
            for (int j = i; j < versions.length; j++) {
                Comparable high = c[j];

        return new MavenContext(
                invokerRequest, true, (MavenOptions) invokerRequest.options().orElse(null));
    }

    @Override
    protected int execute(MavenContext context) throws Exception {
        MavenExecutionRequest request = prepareMavenExecutionRequest();
        toolchains(context, request);
        populateRequest(context, context.lookup, request);

Finally, the identity of our heroes is protected! 🥷

It also re-declares `id: int`. By doing this, we are making a **contract** with the API clients, so that they can always expect the `id` to be there and to be an `int` (it will never be `None`).

/// tip

Having the return model ensure that a value is always available and always `int` (not `None`) is very useful for the API clients, they can write much simpler code having this certainty.