How to use the builtins.slice function in builtins

obj.push({ key: key, value: value });
                    };
                    if (args) {
                        for (let arg of args) {
                            obj.__setitem__(arg[0], arg[1]);
                        }
                    }
                    return obj;
                };
                functionTable['__builtin__.bytearray'] = function(data, encoding) {
                    return { data: data, encoding: encoding };
                };
                functionTable['builtins.bytearray'] = function(data) {
                    return { data: data };
                };
                functionTable['builtins.slice'] = function(start, stop, step) {
                    return { start: start, stop: stop, step: step };
                }
                functionTable['cloudpickle.cloudpickle._builtin_type'] = function(name) {
                    return name;
                }

                let unknownNameMap = new Set();
                let knownPackageMap = new Set([ 
                    'sklearn', 'collections', '__builtin__', 'builtins',
                    'copy_reg', 'joblib','xgboost', 'lightgbm', 'gensim', 'numpy'
                ]);

                let function_call = (name, args) => {
                    let func = functionTable[name];
                    if (func) {
                        return func.apply(null, args);