* removeAll}{@code (occurrencesToRemove)}, which removes all occurrences of elements that appear
   * in {@code occurrencesToRemove}. However, this operation <i>is</i> equivalent to, albeit
   * sometimes more efficient than, the following:
   *
   * <pre>{@code
   * for (E e : occurrencesToRemove) {
   *   multisetToModify.remove(e);
   * }
   * }</pre>
   *

  public final V getOrDefault(@CheckForNull Object key, @CheckForNull V defaultValue) {
    /*
     * Even though it's weird to pass a defaultValue that is null, some callers do so. Those who
     * pass a literal "null" should probably just use `get`, but I would expect other callers to
     * pass an expression that *might* be null. This could happen with:
     *
     * - a `getFooOrDefault(@CheckForNull Foo defaultValue)` method that returns