new IntegerDiv10(11), "eleven",
            new IntegerDiv10(35), "thirty five",
            new IntegerDiv10(12), "twelve");

    assertThrows(IllegalArgumentException.class, () -> ImmutableSortedMap.copyOf(original));
  }

  public void testImmutableMapCopyOfImmutableSortedMap() {
    IntegerDiv10 three = new IntegerDiv10(3);
    IntegerDiv10 eleven = new IntegerDiv10(11);

    }

    /**
     * Adds {@code element} to the {@code ImmutableList}.
     *
     * @param element the element to add
     * @return this {@code Builder} object
     * @throws NullPointerException if {@code element} is null
     */
    @CanIgnoreReturnValue
    @Override
    public Builder<E> add(E element) {
      super.add(element);
      return this;
    }

    /**

      stackWithLastReturnedElementAtTop.pop();
      stackWithLastReturnedElementAtTop.push(e);
    }

    /**
     * Moves the given element from its current position in {@link #nextElements} to the top of the
     * stack so that it is returned by the next call to {@link Iterator#next()}. If the element is
     * not in {@link #nextElements}, this method throws an {@link UnknownElementException}.
     *

   *
   * @throws IllegalArgumentException if {@code node} is not an element of this network
   */
  int outDegree(N node);

  /**
   * Returns the nodes which are the endpoints of {@code edge} in this network.
   *
   * @throws IllegalArgumentException if {@code edge} is not an element of this network
   */
  EndpointPair<N> incidentNodes(E edge);

  /**

  }

  /**
   * Returns an iterable that applies {@code convert} to each element of {@code fromIterable}. The
   * conversion is done lazily.
   *
   * <p>The returned iterable's iterator supports {@code remove()} if the input iterator does. After
   * a successful {@code remove()} call, {@code fromIterable} no longer contains the corresponding
   * element.
   */
  /*

    MinMaxPriorityQueue<Element> queue = MinMaxPriorityQueue.create();
    int range = Element.values().length;
    for (int iter = 0; iter < reduceIterationsIfGwt(1000); iter++) {
      for (int i = 0; i < 100; i++) {
        Element element = Element.values()[random.nextInt(range)];
        elements.add(element);
        queue.add(element);
      }

    }

    /**
     * Adds {@code element} to the {@code ImmutableSortedSet}. If the {@code ImmutableSortedSet}
     * already contains {@code element}, then {@code add} has no effect. (only the previously added
     * element is retained).
     *
     * @param element the element to add
     * @return this {@code Builder} object
     * @throws NullPointerException if {@code element} is null
     */
    @CanIgnoreReturnValue

   * #add(Object, int) add}{@code (element, 1)} instead.
   *
   * @param element the element to add one occurrence of; may be null only if explicitly allowed by
   *     the implementation
   * @return {@code true} always, since this call is required to modify the multiset, unlike other
   *     {@link Collection} types

   * #add(Object, int) add}{@code (element, 1)} instead.
   *
   * @param element the element to add one occurrence of; may be null only if explicitly allowed by
   *     the implementation
   * @return {@code true} always, since this call is required to modify the multiset, unlike other
   *     {@link Collection} types

      if (exception == null) {
        exception = ioe
      }
    }
  }
  if (exception != null) {
    throw exception
  }
}

internal fun <E> MutableList<E>.addIfAbsent(element: E) {
  if (!contains(element)) add(element)
}

internal fun Exception.withSuppressed(suppressed: List<Exception>): Throwable =
  apply {
    for (e in suppressed) addSuppressed(e)
  }