class_of_active_record_descendant

# File activerecord/lib/active_record/base.rb, line 1341
        def class_of_active_record_descendant(klass)
          if klass.superclass == Base || klass.superclass.abstract_class?
            klass
          elsif klass.superclass.nil?
            raise ActiveRecordError, "#{name} doesn't belong in a hierarchy descending from ActiveRecord"
          else
            class_of_active_record_descendant(klass.superclass)
          end
        end