* added.
   *
   * @throws NullPointerException if {@code exceptions} is null
   * @throws IllegalArgumentException if {@code exceptions} is empty
   */
  static RuntimeException create(Collection<? extends Throwable> exceptions) {
    if (exceptions.size() == 0) {
      throw new IllegalArgumentException("Can't create an ExceptionCollection with no exceptions");
    }
    if (exceptions.size() == 1) {

        C filtered1 = filter(unfiltered, EVEN);
        C filtered2 = filter(filtered1, PRIME_DIGIT);

        assertThrows(IllegalArgumentException.class, () -> filtered2.add(4));

        assertThrows(IllegalArgumentException.class, () -> filtered2.add(3));

        filtered2.add(2);
      }
    }

    public void testClearFilterFiltered() {

              e -> e instanceof ConcurrentModificationException)
          .put(ExecutionException.class, e -> e instanceof ExecutionException)
          .put(IllegalArgumentException.class, e -> e instanceof IllegalArgumentException)
          .put(IllegalStateException.class, e -> e instanceof IllegalStateException)
          .put(IndexOutOfBoundsException.class, e -> e instanceof IndexOutOfBoundsException)

          .put(ExecutionError.class, e -> e instanceof ExecutionError)
          .put(ExecutionException.class, e -> e instanceof ExecutionException)
          .put(IllegalArgumentException.class, e -> e instanceof IllegalArgumentException)
          .put(IllegalStateException.class, e -> e instanceof IllegalStateException)
          .put(IndexOutOfBoundsException.class, e -> e instanceof IndexOutOfBoundsException)

              e -> e instanceof ConcurrentModificationException)
          .put(ExecutionException.class, e -> e instanceof ExecutionException)
          .put(IllegalArgumentException.class, e -> e instanceof IllegalArgumentException)
          .put(IllegalStateException.class, e -> e instanceof IllegalStateException)
          .put(IndexOutOfBoundsException.class, e -> e instanceof IndexOutOfBoundsException)

  @CollectionFeature.Require(SUPPORTS_ADD)
  public void testAddOccurrencesNegative() {
    assertThrows(IllegalArgumentException.class, () -> getMultiset().add(e0(), -1));
  }

  @CollectionFeature.Require(SUPPORTS_ADD)
  public void testAddTooMany() {
    getMultiset().add(e3(), Integer.MAX_VALUE);
    assertThrows(IllegalArgumentException.class, () -> getMultiset().add(e3()));
    assertEquals(Integer.MAX_VALUE, getMultiset().count(e3()));

 *     visit(t.getGenericComponentType());
 *   }
 *   protected void visitTypeVariable(TypeVariable<?> t) {
 *     throw new IllegalArgumentException("Cannot contain type variable.");
 *   }
 *   protected void visitWildcardType(WildcardType t) {
 *     throw new IllegalArgumentException("Cannot contain wildcard type.");
 *   }
 * }.visit(type);
 * }
 *

  }

  public void testGetOnlyElement_noDefault_moreThanOneLessThanFiveElements() {
    Iterator<String> iterator = asList("one", "two").iterator();
    IllegalArgumentException expected =
        assertThrows(IllegalArgumentException.class, () -> getOnlyElement(iterator));
    assertThat(expected).hasMessageThat().isEqualTo("expected one element but was: <one, two>");
  }

  }

  private void assertSetCountNegativeOldCount() {
    try {
      getMultiset().setCount(e3(), -1, 1);
      fail("calling setCount() with a negative oldCount should throw IllegalArgumentException");
    } catch (IllegalArgumentException expected) {
    }
  }

  // Negative oldCount.

  @CollectionFeature.Require(SUPPORTS_ADD)
  public void testSetCountConditional_negativeOldCount_addSupported() {

    assertEquals(15, multimap.expectedValuesPerKey);
  }

  public void testCreateFromIllegalSizes() {
    assertThrows(IllegalArgumentException.class, () -> HashMultimap.create(-20, 15));

    assertThrows(IllegalArgumentException.class, () -> HashMultimap.create(20, -15));
  }

  public void testEmptyMultimapsEqual() {
    Multimap<String, Integer> setMultimap = HashMultimap.create();