//
        // @return : if cannot find path, return null or list that size is 0.
        //
        public List <T> Calculate <T>(T start, T goal, bool checkObj = false, bool goalCheckObj = false) where T : ITileMapNode
        {
            if (start == null || goal == null)
            {
                return(null);
            }

            return(pathFinder.Calculate(start, goal, checkObj, goalCheckObj));
        }