void main() {
Person()
..name = "John"
..age = 30
..sex = "Male"
..describeMyself();
}
class Person {
String? name;
int? age;
String? sex;
Person({this.name, this.age, this.sex});
void describeMyself() {
print('Hello my name is $name, I am $age years old');
}
}