private Object convertToEdgeId(final Graph graph, final String outVertexName, String edgeLabel, final String inVertexName) {
        return graph.traversal().V().has("name", outVertexName).outE(edgeLabel).as("e").inV().has("name", inVertexName).<Edge>select("e").next().id();
    }
@author Stephen Mallette (http://stephen.genoprime.com)
gremlin-groovy/src/test/java/org/apache/tinkerpop/gremlin/groovy/jsr223/GremlinGroovyScriptEngineOverGraphTest.java