BankCardNumberValidator constructor Null safety

1. baguette
2. BankCardNumberValidator
3. BankCardNumberValidator
4. BankCardNumberValidator constructor

BankCardNumberValidator class

1. Constructors
2. BankCardNumberValidator
3. Properties
4. hashCode
5. runtimeType
6. Methods
7. noSuchMethod
8. toString
9. validate
10. Operators
11. operator ==