Comparison between class and traits in Scala
| Singleton | Can create new instance | Can have a constructor | Can be inherited | |
| Class | No | Yes | Yes | Yes |
| Abstract class | No | No | Yes | Yes |
| Trait | No | No | No | Yes |
| Object | Yes | No | No | No |
Also a small trick: Since an object cannot be inherited, we need to create a trait (a trait make sure the object won’t have a constructor) with the common values and functions of the objects we wanted to create, then both object would inherit the trait, with one object expanding on the trait.
This construction can be applied to perform Enumeration inheritance in Scala (since Enums by convention are created as objects)