code: public List<PlanNode> findAllAtOrBelow( Traversal order,
                                              Type firstTypeToFind,
                                              Type... additionalTypesToFind ) {
          return findAllAtOrBelow(order, EnumSet.of(firstTypeToFind, additionalTypesToFind));
      }
docs: Find all of the nodes with one of the specified types that are at or below this node.
  
  @param order the order to traverse; may not be null
  @param firstTypeToFind the first type of node to find; may not be null
  @param additionalTypesToFind the additional types of node to find; may not be null
  @return the collection of nodes that are at or below this node that all have one of the supplied types; never null but
  possibly empty