@Override
    public Set<TraverserRequirement> getRequirements() {
        return Collections.singleton(TraverserRequirement.PATH);
    }
@author Marko A. Rodriguez (http://markorodriguez.com)
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/step/map/EdgeOtherVertexStep.java