return AbstractValueGraph.this.edges();
      }

      @Override
      public boolean isDirected() {
        return AbstractValueGraph.this.isDirected();
      }

      @Override
      public boolean allowsSelfLoops() {
        return AbstractValueGraph.this.allowsSelfLoops();
      }

      @Override
      public ElementOrder<N> nodeOrder() {
        return AbstractValueGraph.this.nodeOrder();
      }

      return delegate().hasEdgeConnecting(transpose(endpoints));
    }
  }

  // NOTE: this should work as long as the delegate graph's implementation of edges() (like that of
  // AbstractValueGraph) derives its behavior from calling successors().
  private static final class TransposedValueGraph<N, V> extends ForwardingValueGraph<N, V> {
    private final ValueGraph<N, V> graph;