default Set<TraverserRequirement> getRequirements(final Type type) {
            return getRequirementsByType().getOrDefault(type, Collections.emptySet());
        }
Return any {@link TraverserRequirement}s necessary for this service call for the supplied execution
{@link Type}.
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/structure/service/Service.java