def variation(id)
      variations.select { |v| v.id.split(':').last == id }.first
    end
def variation(id)
      variations.select { |v| v.id.split(':').last == id }.first
    end
Find a variation in this Family by the Font Variation Description
 @param id [String] Family/Font variation ID/Description (e.g. n4 or i7)