return null;
        }

        /**
         * Creates a list from an array of configuration ID values.
         *
         * @param values array of configuration ID strings
         * @return list containing all values from the array
         */
        private static List<String> createConfigIdList(final String[] values) {
            final List<String> idList = new ArrayList<>();

    abstract <E> SortedMultiset<E> subMultiset(
        SortedMultiset<E> multiset, List<Entry<E>> entries, int targetEntry);
  }

  private void testSubMultisetEntrySet(SubMultisetSpec spec) {
    List<Entry<E>> entries = copyToList(sortedMultiset.entrySet());
    for (int i = 0; i < entries.size(); i++) {
      List<Entry<E>> expected = spec.expectedEntries(i, entries);

 * a network interceptor and [exchange] must be non-null.
 */
class RealInterceptorChain(
  internal val call: RealCall,
  private val interceptors: List<Interceptor>,
  private val index: Int,
  internal val exchange: Exchange?,
  internal val request: Request,
  internal val connectTimeoutMillis: Int,
  internal val readTimeoutMillis: Int,

to take advantage of sweet Kotlin features.

#### Credentials.basic()

The username and password parameters to `Credentials.basic()` are now non-null strings. In OkHttp
3.x, null would yield a username or password of "null".

#### HttpUrl.queryParameterValues()

The return type of `HttpUrl.queryParameterValues()` is `List<String?>`. Lists that may contain null

        // Arrange: program send() to simulate first, next, next(NO_MORE_FILES)
        List<String[]> batches = new ArrayList<>();
        batches.add(new String[] { ".", "..", "a", "b" }); // first batch, dot entries filtered
        batches.add(new String[] { "c" }); // second batch
        batches.add(new String[] {}); // last -> NO_MORE_FILES

        // send() answer that mutates the provided response

For example, when you type `python` in the terminal, the operating system looks for a program called `python` in the **first directory** in that list.

If it finds it, then it will **use it**. Otherwise it keeps looking in the **other directories**.

### Installing Python and Updating the `PATH` { #installing-python-and-updating-the-path }

   *
   * @param event event to post.
   */
  public void post(Object event) {
    Iterator<Subscriber> eventSubscribers = subscribers.getSubscribers(event);
    if (eventSubscribers.hasNext()) {
      dispatcher.dispatch(event, eventSubscribers);
    } else if (!(event instanceof DeadEvent)) {
      // the event had no subscribers and was not itself a DeadEvent
      post(new DeadEvent(this, event));
    }
  }

  }

  public void testAny() {
    List<String> list = new ArrayList<>();
    Predicate<String> predicate = equalTo("pants");

    assertFalse(any(list, predicate));
    list.add("cool");
    assertFalse(any(list, predicate));
    list.add("pants");
    assertTrue(any(list, predicate));
  }

  public void testAll() {
    List<String> list = new ArrayList<>();

        return this.connection.getRequestProperty(key);
    }

    @Override
    public Map<String, List<String>> getRequestProperties() {
        final Map<String, List<String>> map = new HashMap<>();
        for (final Entry<String, List<String>> entry : this.requestProperties.entrySet()) {
            map.put(entry.getKey(), Collections.unmodifiableList(entry.getValue()));
        }

   * still throw if the address has a scope ID that fails validation against the interfaces on the
   * machine.
   *
   * @param ipString {@code String} to evaluated as an IP URI host string literal
   * @return {@code true} if the argument is a valid IP URI host
   */
  public static boolean isUriInetAddress(String ipString) {
    return forUriStringOrNull(ipString, /* parseScope= */ false) != null;
  }

  /**