old_contents: from ladon.ladonizer import ladonize
  
  
  class Calculator(object):
  
      @ladonize(int,int,rtype=int)
      def add(self,a,b):
          return a+b
  
new_contents: from __future__ import absolute_import # only needed for python 2.7
  from ladon.ladonizer import ladonize
  
  
  class Calculator(object):
  
      @ladonize(int,int,rtype=int)
      def add(self,a,b):
          return a+b
  
subject: fix to example for python 2.7 (it did relative imports)