In the following code include module is used. The way I see it if include module is removed then also an instance method would be created. Then why user include module ?

<http://github.com/rails/rails/blob/master/activerecord/lib/active_record/associations.rb#L1416>

```
  include Module.new {
          class_eval <<-RUBY, __FILE__, __LINE__ + 1
            def destroy                     # def destroy
              super                         #   super
              #{reflection.name}.clear      #   posts.clear
            end                             # end
          RUBY
        }

```