previous_changes

# File activerecord/lib/active_record/attribute_methods/dirty.rb, line 116
      def previous_changes # :nodoc:
        unless previous_mutation_tracker.equal?(mutations_before_last_save)
          ActiveSupport::Deprecation.warn(            The behavior of `previous_changes` inside of after callbacks is            deprecated without replacement. In the next release of Rails,            this method inside of `after_save` will return the changes that            were just saved..strip_heredoc)
        end
        previous_mutation_tracker.changes
      end