how to generate enums in built value
class VehicleType extends EnumClass {
// these are the fields it will be according to your need
static const VehicleType car = _$car;
static const VehicleType train = _$train;
static const VehicleType bmw = _$BMW;
static const VehicleType tesla = _$Tesla;
static const VehicleType price = _$10000;
// below functions will always be constant
const VehicleType._(String name) : super(name);
static BuiltSet<VehicleType> get values => _$values;
static VehicleType valueOf(String name) => _$valueOf(name);
}