}
  }

  private fun <T> withLocale(
    locale: Locale,
    block: () -> T,
  ): T {
    val previous = Locale.getDefault()
    try {
      Locale.setDefault(locale)
      return block()
    } finally {
      Locale.setDefault(previous)
    }
  }

  @Test fun testIllegalCharsetName() {
    val mediaType = parse("text/plain; charset=\"!@#$%^&*()\"")

    }

    /**
     * Checks if a previous page exists before the current page.
     *
     * @return true if a previous page exists, false otherwise
     */
    public boolean isExistPrePage() {
        return existPrePage;
    }

    /**
     * Sets whether a previous page exists before the current page.
     *
     * @param existPrePage true if a previous page exists, false otherwise
     */

    }

    /**
     * Checks if a previous page exists.
     *
     * @return true if a previous page exists, false otherwise
     */
    public boolean isExistPrePage() {
        return existPrePage;
    }

    /**
     * Sets whether a previous page exists.
     *
     * @param existPrePage true if a previous page exists, false otherwise
     */

# Classes as Dependencies { #classes-as-dependencies }

Before diving deeper into the **Dependency Injection** system, let's upgrade the previous example.

## A `dict` from the previous example { #a-dict-from-the-previous-example }

In the previous example, we were returning a `dict` from our dependency ("dependable"):

{* ../../docs_src/dependencies/tutorial001_an_py310.py hl[9] *}

        case OPEN:
          C previous = domain.previous(endpoint);
          return (previous == null) ? Cut.belowAll() : new AboveValue<>(previous);
      }
      throw new AssertionError();
    }

    @Override
    Cut<C> withUpperBoundType(BoundType boundType, DiscreteDomain<C> domain) {
      switch (boundType) {
        case CLOSED:
          C previous = domain.previous(endpoint);

  public void fetch(HttpUrl url) throws IOException {
    // Skip hosts that we've visited many times.
    AtomicInteger hostnameCount = new AtomicInteger();
    AtomicInteger previous = hostnames.putIfAbsent(url.host(), hostnameCount);
    if (previous != null) hostnameCount = previous;
    if (hostnameCount.getAndIncrement() >= hostLimit) return;

    Request request = new Request.Builder()
        .url(url)
        .build();

    }

    /**
     * Checks if there is a previous page available.
     *
     * @return true if there is a previous page, false otherwise
     */
    public boolean isExistPrePage() {
        return existPrePage;
    }

    /**
     * Sets whether there is a previous page available.
     *
     * @param existPrePage true if there is a previous page, false otherwise
     */

  }

  @Override
  public final boolean hasPrevious() {
    return backingIterator().hasPrevious();
  }

  @Override
  @ParametricNullness
  public final T previous() {
    return transform(backingIterator().previous());
  }

  @Override
  public final int nextIndex() {
    return backingIterator().nextIndex();
  }

  @Override
  public final int previousIndex() {

  }

  @Override
  public final boolean hasPrevious() {
    return backingIterator().hasPrevious();
  }

  @Override
  @ParametricNullness
  public final T previous() {
    return transform(backingIterator().previous());
  }

  @Override
  public final int nextIndex() {
    return backingIterator().nextIndex();
  }

  @Override
  public final int previousIndex() {

   *
   * <p>{@code putInstance(Foo.class, foo)} is equivalent to {@code
   * putInstance(TypeToken.of(Foo.class), foo)}.
   *
   * @return the value previously associated with this class (possibly {@code null}), or {@code
   *     null} if there was no previous entry.
   */
  @CanIgnoreReturnValue
  <T extends B> @Nullable T putInstance(Class<@NonNull T> type, @ParametricNullness T value);

  /**