* opening the data stream.
   *
   * <p>The default implementation returns {@link Optional#absent}. Some sources, such as a {@code
   * CharSequence}, may return a non-absent value. Note that in such cases, it is <i>possible</i>
   * that this method will return a different number of chars than would be returned by reading all
   * of the chars.
   *

	h, ok := config.HelpSubSysMap[subSys]
	if !ok {
		return Help{}, config.Errorf("unknown sub-system %s", subSys)
	}
	if key != "" {
		value, ok := h.Lookup(key)
		if !ok {
			return Help{}, config.Errorf("unknown key %s for sub-system %s",
				key, subSys)
		}
		h = config.HelpKVS{value}
	}

	help := config.HelpKVS{}

	// Only for multiple targets, make sure
	// to list the ENV, for regular k/v EnableKey is

  * Kube-Proxy now defaults to an iptables-based proxy. If the --proxy-mode flag is
specified while starting kube-proxy (‘userspace’ or ‘iptables’), the flag value
will be respected. If the flag value is not specified, the kube-proxy respects
the Node object annotation: ‘net.beta.kubernetes.io/proxy-mode’. If the
annotation is not specified, then ‘iptables’ mode is the default. If kube-proxy

)

// Buffered input.

// Reader implements buffering for an io.Reader object.
// A new Reader is created by calling [NewReader] or [NewReaderSize];
// alternatively the zero value of a Reader may be used after calling [Reset]
// on it.
type Reader struct {
	buf          []byte
	rd           io.Reader // reader provided by the client
	r, w         int       // buf read and write positions

     */
    @Override
    public int getSendBufferSize() {
        return this.snd_buf_size;
    }

    /**
     * Gets the negotiated flags2 value.
     *
     * @return negotiated flags2
     */
    public int getNegotiatedFlags2() {
        return this.negotiatedFlags2;
    }

    /**
     * {@inheritDoc}
     *

          @Override
          public Adder apply(Adder adder) {
            return new FailsToForwardReturnValue(adder);
          }
        },
        "add(",
        "Return value");
  }

  public void testFailsToPropagateException() {
    assertFailure(
        Adder.class,
        new Function<Adder, Adder>() {
          @Override
          public Adder apply(Adder adder) {

        }
        try {
            return ValidationReportLevel.valueOf(level.toUpperCase(Locale.ENGLISH));
        } catch (IllegalArgumentException e) {
            logger.warn(
                    "Invalid value specified for property {}: '{}'. Supported values are (case insensitive): {}",
                    Constants.MAVEN_PLUGIN_VALIDATION,
                    level,
                    Arrays.toString(ValidationReportLevel.values()));

type naughtyDisk struct {
	// The real disk
	disk StorageAPI
	// Programmed errors: API call number => error to return
	errors map[int]error
	// The error to return when no error value is programmed
	defaultErr error
	// The current API call number
	callNR int
	// Data protection
	mu sync.Mutex
}

func newNaughtyDisk(d StorageAPI, errs map[int]error, defaultErr error) *naughtyDisk {

	}
	if !m.checkSeq(msg.Seq) {
		return
	}
	m.recvMu.Lock()
	defer m.recvMu.Unlock()
	if cap(m.inbound) == 0 {
		m.disconnect("did not expect inbound message", true)
		return
	}
	// Note, on EOF no value can be sent.
	if msg.Flags&FlagEOF != 0 {
		if len(msg.Payload) > 0 {
			gridLogIf(m.ctx, fmt.Errorf("muxServer: EOF message with payload"))
		}
		if m.inbound != nil {
			xioutil.SafeClose(m.inbound)

---

Але якщо Вам цікаво розібратися в цьому конкретному прикладі коду і Вам ще не набридло, ось кілька додаткових деталей.

#### Рядок із `value.startswith()`

Звернули увагу? Рядок із `value.startswith()` може приймати кортеж, і тоді він перевірятиме кожне значення в кортежі:

{* ../../docs_src/query_params_str_validations/tutorial015_an_py310.py ln[16:19] hl[17] *}