strange output on calling base class method from extended module
===

what I want to achieve is something like below i.e. calling a base class method from extended modules method

    class BaseClass
      def behavior
        puts 'base class behavior'
      end
    end
    
    module ChildModule
      def behavior
       super.behavior
       puts 'child module behavior'
      end
    end
    
    o = BaseClass.new
    o.extend ChildModule
    o.behavior
    
and it outoputs as follow(with ruby 1.9.2p290 (2011-07-09 revision 32553) [x86_64-linux])

    base class behavior
    t.rb:9:in `behavior': undefined method `behavior' for nil:NilClass (NoMethodError)
           from t.rb:16:in `<main>'


I guess that, I can not use super, super does not exist there in module. But it prints out that line from super method, is that strange?

How do I achieve it what I want above?


