{* ../../docs_src/body_nested_models/tutorial002_py310.py hl[12] *}

## Set types { #set-types }

But then we think about it, and realize that tags shouldn't repeat, they would probably be unique strings.

And Python has a special data type for sets of unique items, the `set`.

Then we can declare `tags` as a set of strings:

 * @since 20.0
 */
@Beta
public interface MutableGraph<N> extends Graph<N> {

  /**
   * Adds {@code node} if it is not already present.
   *
   * <p><b>Nodes must be unique</b>, just as {@code Map} keys must be. They must also be non-null.
   *
   * @return {@code true} if the graph was modified as a result of this call
   */
  @CanIgnoreReturnValue
  boolean addNode(N node);

  /**

 * comparator is not consistent with {@code equals}.
 *
 * <p>The {@code standard} methods are not guaranteed to be thread-safe, even when all of the
 * methods that they depend on are thread-safe.
 *
 * @author Mike Bostock
 * @author Louis Wasserman
 * @since 2.0
 */
@GwtCompatible
public abstract class ForwardingMapEntry<K extends @Nullable Object, V extends @Nullable Object>

        assertTrue(resultString.contains("totalAvailableEntries=5"), "toString should contain the total available entries.");
    }

    /**
     * Tests the empty write methods to ensure they do nothing and return 0.
     */
    @Test
    void testWriteMethods() {
        NetShareEnumResponse response = new NetShareEnumResponse();
        byte[] dst = new byte[10];

   * one of the listener's callbacks will execute at once. However, multiple listeners' callbacks
   * may execute concurrently, and listeners may execute in an order different from the one in which
   * they were registered.
   *
   * <p>RuntimeExceptions thrown by a listener will be caught and logged. Any exception thrown
   * during {@code Executor.execute} (e.g., a {@code RejectedExecutionException}) will be caught and

* `fixedquery`: has the exact value `fixedquery`.
* `$`: ends there, doesn't have any more characters after `fixedquery`.

If you feel lost with all these **"regular expression"** ideas, don't worry. They are a hard topic for many people. You can still do a lot of stuff without needing regular expressions yet.

Now you know that whenever you need them you can use them in **FastAPI**.

This is just a **quick tutorial / refresher** about Python type hints. It covers only the minimum necessary to use them with **FastAPI**... which is actually very little.

**FastAPI** is all based on these type hints, they give it many advantages and benefits.

But even if you never use **FastAPI**, you would benefit from learning a bit about them.

/// note

   */
  @get:JvmName("proxySelector") val proxySelector: ProxySelector,
) {
  /**
   * Returns a URL with the hostname and port of the origin server. The path, query, and fragment of
   * this URL are always empty, since they are not significant for planning a route.
   */
  @get:JvmName("url")
  val url: HttpUrl =
    HttpUrl
      .Builder()
      .scheme(if (sslSocketFactory != null) "https" else "http")
      .host(uriHost)

   * started execution. It is unclear from the {@code ExecutorService} specification if these should
   * be included, and it's much easier to implement the interpretation that they not be. Finally, a
   * call to {@code shutdown} or {@code shutdownNow} may result in concurrent calls to {@code
   * invokeAll/invokeAny} throwing RejectedExecutionException, although a subset of the tasks may

        // Each setInstance should create a new LogStream
        assertNotNull(instance1);
        assertNotNull(instance2);
        // The second setInstance replaces the first, so they should not be the same
        assertNotSame(instance1, instance2);
        // Getting instance again should return the same as instance2
        assertSame(instance2, LogStream.getInstance());
    }

    @Test