public Optional<DataType> get( Object tree ) {
        return (Optional<DataType>) traversr.get( tree, keys );
    }
public Optional < DataType > get ( Object tree ) { return ( Optional < DataType > ) traversr . get ( tree , keys ) ; }
@param tree tree of Map and List JSON structure to navigate
@return the object you wanted, or null if the object or any step along the path to it were not there