@Override
    public Edge addEdge(final String label, final Vertex inVertex, final Object... keyValues) {
        throw Vertex.Exceptions.edgeAdditionsNotSupported();
    }
@author Marko A. Rodriguez (http://markorodriguez.com)
hadoop-gremlin/src/main/java/org/apache/tinkerpop/gremlin/hadoop/structure/HadoopVertex.java