Exended modules and reject_if in nested_attributes

I have some common class methods in a module ‘active_record_additions’ that I load into a class by Activity by using extend ActiveRecordAdditions The Activity class uses nested_attributes_for with a reject_if method saved in the module ‘active_record_additions’ The problem is that the class methods in ‘active_record_additions’ works when I use them as ordinary class methods, but not as a a method in reject_if. I got the message NameError (undefined method exists_nested_targeting_group?' for class Activity’):

Maybe that method cannot be a class method ? Or can accept_nested use methods in an extend module ? Or anyone thats can give a hint abot whay it does not work ?

Some code snippets The class definition

encoding: utf-8

require ‘active_record_additions’