input: 
  class Sum:
      def __init__(self, x, y):
          self.x = x
          self.y = y
          
      def add(self):
          return self.x + self.y
  
  # Should add 3 and 5 and return 8
  sum_instance = Sum(3, 5)
  output = sum_instance.add()
  print(output) # Output: 8
  
output:     def __init__(self, x, y):
          self.x = x
          self.y = y
          
      def add(self):
          return self.x + self.y