You probably know, that in Javascript (and also Ruby) there is no concept of interfaces. There is only a concept of inheritance, but you can't assume that a certain method or property exists, just because it exists in the parent prototype / class. We want to find out, whether a given object fulfils the requirements to implement the "SantaClausable" interface. We need to implement a method which checks for this interface.

Rules

The SantaClausable interface is implemented, if all of the following methods are defined on an object:
•sayHoHoHo() / say_ho_ho_ho
•distributeGifts() / distribute_gifts
•goDownTheChimney() / go_down_the_chimney

Example


class SantaClaus
    def say_ho_ho_ho
        # Ho Ho Ho!
    end

    def distribute_gifts
        # Gifts for all!
    end

    def go_down_the_chimney
        # Whoosh!
    end
end

class NotSantaClaus
    def say_ho_ho_ho
    end
end

is_santa_clausable(SantaClaus.new) # must return TRUE
is_santa_clausable(NotSantaClaus.new) # must return