StudentCodeValidationError constructor Null safety

1. univalle_app
2. sign_in
3. StudentCodeValidationError
4. StudentCodeValidationError const constructor

StudentCodeValidationError enum

1. Constructors
2. StudentCodeValidationError
3. Values
4. empty
5. Properties
6. hashCode
7. index
8. runtimeType
9. Methods
10. noSuchMethod
11. toString
12. Operators
13. operator ==
14. Constants
15. values