I prefere to not use a capturing group when not necessary

Sorry about that, I'm doing it in Ruby

what language?

You have to define your method like this

class Primes
def self.first(n)
end
end

Are the second level tests in the same "name.key => "num,num,num" format?"
My solution passed the three initial test cases, but for the additional tests, it's outputting numbers instead of the country names.