@Override
  public final void add(int index, E element) {
    throw new UnsupportedOperationException();
  }

  @Override
  public final E remove(int index) {
    throw new UnsupportedOperationException();
  }

  @Override
  public UnmodifiableIterator<E> iterator() {
    return listIterator();
  }

  @Override
  public ImmutableList<E> subList(int fromIndex, int toIndex) {

This would be useful if you want to receive keys that you don't already know.

---

Another useful case is when you want to have keys of another type (e.g., `int`).

That's what we are going to see here.

In this case, you would accept any `dict` as long as it has `int` keys with `float` values:

{* ../../docs_src/body_nested_models/tutorial009_py39.py hl[7] *}

/// tip

---

Другой полезный случай — когда вы хотите, чтобы ключи были другого типа данных, например, `int`.

Именно это мы сейчас и увидим здесь.

В этом случае вы принимаете любой `dict`, пока у него есть ключи типа `int` со значениями типа `float`:

{* ../../docs_src/body_nested_models/tutorial009_py39.py hl[7] *}

/// tip | Совет

package lock

import (
	"os"
	"syscall"
)

// Internal function implements support for both
// blocking and non blocking lock type.
func lockedOpenFile(path string, flag int, perm os.FileMode, lockType int) (*LockedFile, error) {
	switch flag {
	case syscall.O_RDONLY:
		lockType |= syscall.LOCK_SH
	case syscall.O_WRONLY:
		fallthrough
	case syscall.O_RDWR:
		fallthrough

  }

  private static final ImmutableList<Range<Integer>> RANGES;
  private static final int MIN_BOUND = -1;
  private static final int MAX_BOUND = 1;

  static {
    ImmutableList.Builder<Range<Integer>> builder = ImmutableList.builder();

    builder.add(Range.<Integer>all());

    // Add one-ended ranges
    for (int i = MIN_BOUND; i <= MAX_BOUND; i++) {
      for (BoundType type : BoundType.values()) {

    private final int constant;

    ConstantWeigher(int constant) {
      this.constant = constant;
    }

    @Override
    public int weigh(Object key, Object value) {
      return constant;
    }
  }

  static final class IntKeyWeigher implements Weigher<Integer, Object> {
    @Override
    public int weigh(Integer key, Object value) {
      return key;
    }
  }

  }

  @Benchmark
  int isMathematicalInteger(int reps) {
    int tmp = 0;
    for (int i = 0; i < reps; i++) {
      int j = i & ARRAY_MASK;
      if (DoubleMath.isMathematicalInteger(doubles[j])) {
        tmp++;
      }
    }
    return tmp;
  }

  @Benchmark
  int isPowerOfTwo(int reps) {
    int tmp = 0;
    for (int i = 0; i < reps; i++) {
      int j = i & ARRAY_MASK;

    List<Element> queryList = Lists.newArrayListWithCapacity(numQueries);

    int numGoodQueries = (int) (numQueries * hitRate + 0.5);

    // add good queries
    int size = elementsInSet.size();
    if (size > 0) {
      int minCopiesOfEachGoodQuery = numGoodQueries / size;
      int extras = numGoodQueries % size;

      for (int i = 0; i < minCopiesOfEachGoodQuery; i++) {

      }
    };
  }

  // Implementations for encoding/decoding

  abstract int maxEncodedSize(int bytes);

  abstract void encodeTo(Appendable target, byte[] bytes, int off, int len) throws IOException;

  abstract int maxDecodedSize(int chars);

  abstract int decodeTo(byte[] target, CharSequence chars) throws DecodingException;

  CharSequence trimTrailingPadding(CharSequence chars) {

  @Override public Socket createSocket(String host, int port) throws IOException {
    Socket result = createSocket();

    try {
      result.connect(new InetSocketAddress(host, port));
    } catch (IOException e) {
      result.close();
      throw e;
    }
    return result;
  }

  @Override public Socket createSocket(
      String host, int port, InetAddress localHost, int localPort) throws IOException {