@Override
    public boolean contains(final Object s) {
        return this.map.containsKey(s);
    }
@return true if it is guaranteed that all contained elements/objects are of the same type/class and not null (but not
necessarily, i.e., they can have the same type/class, but we may return false here if it was not analysed/identified)
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/step/util/BulkSet.java