old_contents: import dis
  
  def sum():
      vara = 10
      varb = 10
      sum = vara + varb
      print "vara + varb = %d" % sum
  
  sum()
  
new_contents: import dis
  
  def sum():
      vara = 10
      varb = 10
      sum = vara + varb
      print "vara + varb = %d" % sum
  
  print sum()
  
subject: update dis.py