# File activerecord/lib/active_record/dirty.rb, line 169
169:       def self.extended(base)
170:         base.singleton_class.alias_method_chain(:alias_attribute, :dirty)
171:       end

     # File activerecord/lib/active_record/dirty.rb, line 173
173:       def alias_attribute_with_dirty(new_name, old_name)
174:         alias_attribute_without_dirty(new_name, old_name)
175:         DIRTY_SUFFIXES.each do |suffix|
176:           module_eval "def \#{new_name}\#{suffix}; self.\#{old_name}\#{suffix}; end  # def subject_changed?; self.title_changed?; end\n", __FILE__, __LINE__ + 1
177:         end
178:       end