*/
  protected abstract char @Nullable [] escape(int cp);

  /**
   * Returns the escaped form of a given literal string.
   *
   * <p>If you are escaping input in arbitrary successive chunks, then it is not generally safe to
   * use this method. If an input string ends with an unmatched high surrogate character, then this

default, FastAPI will inspect every item inside and make sure it is serializable as JSON, using the same [JSON Compatible Encoder](../tutorial/encoder.md){.internal-link target=_blank} explained in the tutorial. This is what allows you to return **arbitrary objects**, for example database models.

But if you are certain that the content that you are returning is **serializable with JSON**, you can pass it directly to the response class and avoid the extra overhead that FastAPI would have by...

   */
  protected abstract char @Nullable [] escape(int cp);

  /**
   * Returns the escaped form of a given literal string.
   *
   * <p>If you are escaping input in arbitrary successive chunks, then it is not generally safe to
   * use this method. If an input string ends with an unmatched high surrogate character, then this

   * new stack trace matches that of the current thread.
   *
   * <p>Instances of {@code exceptionClass} are created by choosing an arbitrary public constructor
   * that accepts zero or more arguments, all of type {@code String} or {@code Throwable}
   * (preferring constructors with at least one {@code String}, then preferring constructors with at

  // 1. Tests on a hardcoded dataset for chains starting with median(), quartiles(), and scale(10):

  /** The squares of the 16 integers from 0 to 15, in an arbitrary order. */
  private static final ImmutableList<Double> SIXTEEN_SQUARES_DOUBLES =
      ImmutableList.of(
          25.0, 100.0, 0.0, 144.0, 9.0, 121.0, 4.0, 225.0, 169.0, 64.0, 49.0, 16.0, 36.0, 1.0, 81.0,
          196.0);

  // 1. Tests on a hardcoded dataset for chains starting with median(), quartiles(), and scale(10):

  /** The squares of the 16 integers from 0 to 15, in an arbitrary order. */
  private static final ImmutableList<Double> SIXTEEN_SQUARES_DOUBLES =
      ImmutableList.of(
          25.0, 100.0, 0.0, 144.0, 9.0, 121.0, 4.0, 225.0, 169.0, 64.0, 49.0, 16.0, 36.0, 1.0, 81.0,
          196.0);

### Invalid Return Type Annotations { #invalid-return-type-annotations }

But when you return some other arbitrary object that is not a valid Pydantic type (e.g. a database object) and you annotate it like that in the function, FastAPI will try to create a Pydantic response model from that type annotation, and will fail.

     * <p>{@code [<E>]} will be returned for ArrayList's constructor. When both the class and the
     * constructor have type parameters, the class parameters are prepended before those of the
     * constructor's. This is an arbitrary rule since no existing language spec mandates one way or
     * the other. From the declaration syntax, the class type parameter appears first, but the call
     * syntax may show up in opposite order such as {@code new <A>Foo<B>()}.

   * {@code actual} can be {@code Map<K, V>} and {@code Map<String, Integer>} respectively, or they
   * can be {@code E[]} and {@code String[]} respectively, or even any arbitrary combination
   * thereof.
   *
   * @param formal The type whose type variables or itself is mapped to other type(s). It's almost

    server.enqueue(
      MockResponse
        .Builder()
        .onRequestBody(CloseSocket())
        .build(),
    )
    // Limit the size of the request body that the server holds in memory to an arbitrary
    // 3.5 MBytes so this test can pass on devices with little memory.
    server.bodyLimit = 7 * 512 * 1024
    val connection = server.url("/").toUrl().openConnection() as HttpURLConnection