    # File lib/chef/node/attribute.rb, line 140
          def each_pair(&block)
            get_keys.each do |key|
              value = determine_value(
                get_value(automatic, key),
                get_value(override, key),
                get_value(normal, key),
                get_value(default, key)
              )
              block.call(key, value)
            end
          end