I understood that only Snoopy can bark, and Scoobydoo can't bark ?
So Snoopy.bark() returns "Woof"
But Scoobydoo.bark() should return #undefined ?
Here, both Snoopy and Scoobydoo can bark.
I probably have missed something ?

Warm thank you very much for the reply. I would need to read more carefully with my english. BR

Hi !
the Failing test is for : n = "14"
I checked the "digits" and the "len = 2"
But the error message is : "True should equal False" ? ? ?