### Створення класу `Enum`

Імпортуйте `Enum` і створіть підклас, що наслідується від `str` та `Enum`.

Наслідуючи від `str`, документація API зможе визначити, що значення повинні бути типу `string`, і правильно їх відобразить.

 *
 * @author Mike Bostock
 * @since 2.0
 */
@GwtCompatible
@J2ktIncompatible
public final class EnumBiMap<K extends Enum<K>, V extends Enum<V>> extends AbstractBiMap<K, V> {
  /*
   * J2CL's EnumMap does not need the Class instance, so we can use Object.class instead. (Or we

        assertEquals("test", testValue);
    }

    // Additional test for coverage
    public void test_additionalCoverage() {
        int a = 5;
        int b = 10;
        int sum = a + b;
        assertEquals(15, sum);

        String str = "Hello";
        assertTrue(str.startsWith("H"));
        assertTrue(str.endsWith("o"));
        assertEquals(5, str.length());
    }

        assertEquals("test", testValue);
    }

    // Additional test for coverage
    public void test_additionalCoverage() {
        int a = 5;
        int b = 10;
        int sum = a + b;
        assertEquals(15, sum);

        String str = "Hello";
        assertTrue(str.startsWith("H"));
        assertTrue(str.endsWith("o"));
        assertEquals(5, str.length());
    }

        assertEquals("test", testValue);
    }

    // Additional test for coverage
    public void test_additionalCoverage() {
        int a = 5;
        int b = 10;
        int sum = a + b;
        assertEquals(15, sum);

        String str = "Hello";
        assertTrue(str.startsWith("H"));
        assertTrue(str.endsWith("o"));
        assertEquals(5, str.length());
    }

        assertEquals("test", testValue);
    }

    // Additional test for coverage
    public void test_additionalCoverage() {
        int a = 5;
        int b = 10;
        int sum = a + b;
        assertEquals(15, sum);

        String str = "Hello";
        assertTrue(str.startsWith("H"));
        assertTrue(str.endsWith("o"));
        assertEquals(5, str.length());
    }

 * serialization of funnels. When possible, it is recommended that funnels be implemented as a
 * single-element enum to maintain serialization guarantees. See Effective Java (2nd Edition), Item
 * 3: "Enforce the singleton property with a private constructor or an enum type". For example:
 *
 * {@snippet :
 * public enum PersonFunnel implements Funnel<Person> {
 *   INSTANCE;
 *   public void funnel(Person person, PrimitiveSink into) {

package com.google.common.collect.testing;

import com.google.common.annotations.GwtCompatible;

/**
 * A sample enumerated type we use for testing.
 *
 * @author Kevin Bourrillion
 */
@GwtCompatible
public enum AnEnum {
  A,
  B,
  C,
  D,
  E,
  F

        sum += array[index].hashCode();
      }
    }
    return sum;
  }

  @Benchmark
  int arrayFor(int reps) {
    int sum = 0;
    for (int i = 0; i < reps; i++) {
      for (Object value : array) {
        sum += value.hashCode();
      }
    }
    return sum;
  }

  @Benchmark
  int arrayListIndexed(int reps) {
    int sum = 0;
    for (int i = 0; i < reps; i++) {

    add(-1L);
  }

  /**
   * Returns the current sum. The returned value is NOT an atomic snapshot; invocation in
   * the absence of concurrent updates returns an accurate result, but concurrent updates that occur
   * while the sum is being calculated might not be incorporated.
   *
   * @return the sum
   */
  @Override
  public long sum() {
    long sum = base;
    Cell[] as = cells;
    if (as != null) {