**FastAPI** 🔜 🚧 🌖 ℹ ⚪️➡️ `responses`, & 🌀 ⚫️ ⏮️ 🎻 🔗 ⚪️➡️ 👆 🏷.

🖼, 👆 💪 📣 📨 ⏮️ 👔 📟 `404` 👈 ⚙️ Pydantic 🏷 & ✔️ 🛃 `description`.

& 📨 ⏮️ 👔 📟 `200` 👈 ⚙️ 👆 `response_model`, ✋️ 🔌 🛃 `example`:

```Python hl_lines="20-31"
{!../../docs_src/additional_responses/tutorial003.py!}
```

⚫️ 🔜 🌐 🌀 & 🔌 👆 🗄, & 🎦 🛠️ 🩺:

<img src="/img/tutorial/additional-responses/image01.png">

    if (!hasNext()) throw NoSuchElementException()

    // Compute the next set of routes to attempt.
    val routes = mutableListOf<Route>()
    while (hasNextProxy()) {
      // Postponed routes are always tried last. For example, if we have 2 proxies and all the
      // routes for proxy1 should be postponed, we'll move to proxy2. Only after we've exhausted
      // all the good routes will we attempt the postponed routes.
      val proxy = nextProxy()

 * ordinarily difficult to write iterators for. But using this class, one must implement only the
 * {@link #computeNext} method, and invoke the {@link #endOfData} method when appropriate.
 *
 * <p>Another example is an iterator that skips over null elements in a backing iterator. This could
 * be implemented as:
 *
 * <pre>{@code
 * public static Iterator<String> skipNulls(final Iterator<String> in) {

import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * An immutable builder for {@link Multimap} instances, letting you independently select the desired
 * behaviors (for example, ordering) of the backing map and value-collections. Example:
 *
 * <pre>{@code
 * ListMultimap<UserId, ErrorResponse> errorsByUser =
 *     MultimapBuilder.linkedHashKeys().arrayListValues().build();
 * SortedSetMultimap<String, Method> methodsForName =

      if (array[i] == target) {
        return i;
      }
    }
    return -1;
  }

  /**
   * Returns the values from each provided array combined into a single array. For example, {@code
   * concat(new byte[] {a, b}, new byte[] {}, new byte[] {c}} returns the array {@code {a, b, c}}.
   *
   * @param arrays zero or more {@code byte} arrays

    doTestTrimFrom("x--x", "x--x");
    doTestTrimFrom("x-x-", "x-x");
    doTestTrimFrom("x-xx", "x-xx");
    doTestTrimFrom("x-x--xx---x----x", "x-x--xx---x----x");
    // additional testing using the doc example
    assertEquals("cat", anyOf("ab").trimFrom("abacatbab"));
  }

  private void doTestTrimFrom(String in, String out) {
    // Try a few different matchers which all match '-' and not 'x'

   * convenient.
   *
   * <p>By default, a {@code Builder} will generate maps that iterate over entries in the order they
   * were inserted into the builder, equivalently to {@code LinkedHashMap}. For example, in the
   * above example, {@code WORD_TO_INT.entrySet()} is guaranteed to iterate over the entries in the
   * order {@code "one"=1, "two"=2, "three"=3}, and {@code keySet()} and {@code values()} respect

    )
    assert response.status_code == 200, response.text
    assert response.json() == {
        "username": "johndoe",
        "full_name": "John Doe",
        "email": "johndoe@example.com",
        "disabled": False,
    }


@needs_py310
def test_incorrect_token(client: TestClient):
    response = client.get("/users/me", headers={"Authorization": "Bearer nonexistent"})

    )
    assert response.status_code == 200, response.text
    assert response.json() == {
        "username": "johndoe",
        "full_name": "John Doe",
        "email": "johndoe@example.com",
        "disabled": False,
    }


@needs_py39
def test_incorrect_token(client: TestClient):
    response = client.get("/users/me", headers={"Authorization": "Bearer nonexistent"})

    int size = size();
    for (int i = 0; i < size; i++) {
      dst[offset + i] = get(i);
    }
    return offset + size;
  }

  /**
   * Returns a view of this immutable list in reverse order. For example, {@code ImmutableList.of(1,
   * 2, 3).reverse()} is equivalent to {@code ImmutableList.of(3, 2, 1)}.
   *
   * @return a view of this immutable list in reverse order
   * @since 7.0
   */