ex44.py

class Other(object):

  def override(self):
    print "OTHER override()"

  def implicit(self):
    print "OTHER implicit()"

  def altered(self):
    print "OTHER altered()"

class Child(object):

  def __init__(self):
    self.other = Other()

  def implicit(self):
    self.other.implicit()

  def override(self):
    print "CHILD override()"

  def altered(self):
    print "CHILD, BEFORE OTHER altered()"
    self.other.altered()
    print "CHILD, AFTER OTHER altered()"

son = Child()

son.implicit()
son.override()
son.altered()