text: class AdvancedArithmetic(object):
      def divisorSum(n):
          raise NotImplementedError
  
  
  class Calculator(AdvancedArithmetic):
      def divisorSum(self, n):
          divisor_sum = 0
          for divisor in range(2, n):
              if n % divisor == 0:
                  divisor_sum += divisor
          return divisor_sum + n + (0 if n is 1 else 1)
  