new_contents: class Parent(object):
      def override(self):
          print("PARENT override()")
  
      def implicit(self):
          print("PARENT implicit()")
  
      def alterred(self):
          print("PARENT alterred()")
  
  class Child(Parent):
      def override(self):
          print("CHILD override()")
  
      def implicit(self):
          print("CHILD implicit()")
  
      def alterred(self):
          print("CHILD, BEFORE PARENT alterred()")
          super(Child, self).alterred()
          print("CHILD, AFTER PARENT alterred()")
  
  dad = Parent()
  son = Child()
  
  dad.implicit()
  son.implicit()
  
  dad.override()
  son.override()
  
  dad.alterred()
  son.alterred()
subject: add a file