Наприклад, додаймо [розширення OpenAPI ReDoc для додавання власного логотипа](https://github.com/Rebilly/ReDoc/blob/master/docs/redoc-vendor-extensions.md#x-logo).

### Звичайний **FastAPI** { #normal-fastapi }

Спочатку напишіть ваш застосунок **FastAPI** як зазвичай:

{* ../../docs_src/extending_openapi/tutorial001_py310.py hl[1,4,7:9] *}

    assertEquals(1, DiscreteDomain.longs().offset(0L, 1).longValue());
    assertEquals(Long.MAX_VALUE, DiscreteDomain.longs().offset(0L, Long.MAX_VALUE).longValue());
  }

  public void testLongsOffsetExceptions() {
    assertThrows(IllegalArgumentException.class, () -> DiscreteDomain.longs().offset(0L, -1));
    assertThrows(
        IllegalArgumentException.class, () -> DiscreteDomain.longs().offset(Long.MAX_VALUE, 1));
  }

    RequestBody requestBody = new MultipartBody.Builder()
        .setType(MultipartBody.FORM)
        .addFormDataPart("title", "Square Logo")
        .addFormDataPart("image", "logo-square.png",
            RequestBody.create(
                new File("docs/images/logo-square.png"),
                MEDIA_TYPE_PNG))
        .build();

    Request request = new Request.Builder()

    return result;
  }

  /**
   * Generates a number in [0, 2^numBits) with an exponential distribution. The floor of the log2 of
   * the result is chosen uniformly at random in [0, numBits), and then the result is chosen in that
   * range uniformly at random. Zero is treated as having log2 == 0.
   */
  static BigInteger randomNonNegativeBigInteger(int numBits) {
    int digits = RANDOM_SOURCE.nextInt(numBits);

    Converter<Long, String> reverseConverter = Longs.stringConverter().reverse();
    SerializableTester.reserializeAndAssert(reverseConverter);
  }

  @GwtIncompatible // J2CL generics problem
  public void testSerialization_andThen() {
    Converter<String, Long> converterA = Longs.stringConverter();
    Converter<Long, String> reverseConverter = Longs.stringConverter().reverse();

            ListTestSuiteBuilder.using(new LongsAsListTailSubListGenerator())
                .named("Longs.asList, tail subList"),
            ListTestSuiteBuilder.using(new LongsAsListMiddleSubListGenerator())
                .named("Longs.asList, middle subList"));

    TestSuite suite = new TestSuite();
    for (ListTestSuiteBuilder<Long> builder : builders) {
      suite.addTest(
          builder

        description="Here's a longer description of the custom **OpenAPI** schema",
        routes=app.routes,
    )
    openapi_schema["info"]["x-logo"] = {
        "url": "https://fastapi.tiangolo.com/img/logo-margin/logo-teal.png"
    }
    app.openapi_schema = openapi_schema
    return app.openapi_schema

For example, let's add [ReDoc's OpenAPI extension to include a custom logo](https://github.com/Rebilly/ReDoc/blob/master/docs/redoc-vendor-extensions.md#x-logo).

### Normal **FastAPI** { #normal-fastapi }

First, write all your **FastAPI** application as normally:

{* ../../docs_src/extending_openapi/tutorial001_py310.py hl[1,4,7:9] *}

  }

  /** Returns a {@link HashCode} for a sequence of longs, in big-endian order. */
  private static HashCode toHashCode(long... longs) {
    ByteBuffer bb = ByteBuffer.wrap(new byte[longs.length * 8]).order(ByteOrder.LITTLE_ENDIAN);
    for (long x : longs) {
      bb.putLong(x);
    }
    return HashCode.fromBytes(bb.array());
  }

  public void testParanoid() {

### Markdown link to static assets { #markdown-link-to-static-assets }

These are links to static assets:

* [FastAPI Logo](https://fastapi.tiangolo.com/img/fastapi-logo.png)
* [FastAPI CSS](https://fastapi.tiangolo.com/css/fastapi.css)
* [FastAPI JS](https://fastapi.tiangolo.com/js/fastapi.js)

Tool should NOT add language code to their URLs.