public static <A, B> GraphTraversal<A, B> call(final String service, final GValue<Map> params, final Traversal<?, Map<?,?>> childTraversal) {
        return __.<A>start().call(service, params, childTraversal);
    }
@see GraphTraversal#call(String, GValue, Traversal)
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/dsl/graph/__.java