addEdge(N1, N1, E11);
    assertThat(network.outDegree(N1)).isEqualTo(2);
    addEdge(N2, N1, E12);
    assertThat(network.outDegree(N1)).isEqualTo(3);
  }

  // Element Mutation

  @Test
  public void addEdge_existingNodes() {
    assume().that(graphIsMutable()).isTrue();

    // Adding nodes initially for safety (insulating from possible future

	}

	// next token must be ',' or ']'
	switch c = d.skipSpaces(); c {
	case ',':
		d.skipSpaces()
		goto scan
	case ']':
		goto out
	default:
		err = d.mkError(ErrSyntax, "after array element")
	}

out:
	d.depth--
	return array, err
}

// object accept valid JSON array value
func (d *Decoder) object() (map[string]interface{}, error) {
	d.depth++

                  protected Set<String> create(String[] elements) {
                    return ImmutableMultiset.copyOf(elements).elementSet();
                  }
                })
            .named("ImmutableMultiset, element set")
            .withFeatures(
                CollectionSize.ANY,
                CollectionFeature.SERIALIZABLE,
                CollectionFeature.ALLOWS_NULL_QUERIES)
            .createTestSuite());

    return CollectCollectors.toImmutableListMultimap(keyFunction, valueFunction);
  }

  /**
   * Returns a {@code Collector} accumulating entries into an {@code ImmutableListMultimap}. Each
   * input element is mapped to a key and a stream of values, each of which are put into the
   * resulting {@code Multimap}, in the encounter order of the stream and the encounter order of the
   * streams of values.
   *
   * <p>Example:
   *

  static final String ERROR_SELF_LOOP = "self-loops are not allowed";
  static final String ERROR_EDGE_NOT_IN_GRAPH =
      "Should not be allowed to pass an edge that is not an element of the graph.";
  static final String ERROR_ADDED_SELF_LOOP = "Should not be allowed to add a self-loop edge.";
  static final String ERROR_ADDED_PARALLEL_EDGE = "Should not be allowed to add a parallel edge.";

    this(multimap.keySet().size());
    putAll(multimap);
  }

  /**
   * Adds a new node for the specified key-value pair before the specified {@code nextSibling}
   * element, or at the end of the list if {@code nextSibling} is null. Note: if {@code nextSibling}
   * is specified, it MUST be for a node for the same {@code key}!
   */
  @CanIgnoreReturnValue
  private Node<K, V> addNode(

     */
    protected abstract List<Integer> create(Integer[] elements);

    @Override
    public Integer[] createArray(int length) {
      return new Integer[length];
    }

    /** Returns the original element list, unchanged. */
    @Override
    public List<Integer> order(List<Integer> insertionOrder) {
      return insertionOrder;
    }
  }

  @J2ktIncompatible
  @GwtIncompatible // used only from suite

     */
    protected abstract List<Double> create(Double[] elements);

    @Override
    public Double[] createArray(int length) {
      return new Double[length];
    }

    /** Returns the original element list, unchanged. */
    @Override
    public List<Double> order(List<Double> insertionOrder) {
      return insertionOrder;
    }
  }

  @J2ktIncompatible
  @GwtIncompatible // used only from suite

    return CollectCollectors.toImmutableListMultimap(keyFunction, valueFunction);
  }

  /**
   * Returns a {@code Collector} accumulating entries into an {@code ImmutableListMultimap}. Each
   * input element is mapped to a key and a stream of values, each of which are put into the
   * resulting {@code Multimap}, in the encounter order of the stream and the encounter order of the
   * streams of values.
   *
   * <p>Example:

		// Output: 42
	}

In C, a function argument written as a fixed size array
actually requires a pointer to the first element of the array.
C compilers are aware of this calling convention and adjust
the call accordingly, but Go cannot. In Go, you must pass
the pointer to the first element explicitly: C.f(&C.x[0]).

Calling variadic C functions is not supported. It is possible to