public default GraphTraversal<S, Vertex> mergeV(final Traversal<?, Map<Object, Object>> searchCreate) {
        this.asAdmin().getGremlinLang().addStep(Symbols.mergeV, searchCreate);
        final MergeVertexStep<S> step = null == searchCreate ? new MergeVertexStep(this.asAdmin(), false, (Map) null) :
                new MergeVertexStep(this.asAdmin(), false, searchCreate.asAdmin());
        return this.asAdmin().addStep(step);
    }
Performs a merge (i.e. upsert) style operation for an {@link Vertex} using a {@code Map} as an argument.
The {@code Map} represents search criteria and will match each of the supplied key/value pairs where the keys
may be {@code String} property values or a value of {@link T}. If a match is not made it will use that search
criteria to create the new {@link Vertex}.

 @param searchCreate This anonymous {@link Traversal} must produce a {@code Map} that may have a keys of
 {@link T} or a {@code String}.
 @since 3.6.0
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/dsl/graph/GraphTraversal.java