# File lib/chef/node/attribute.rb, line 418
      def method_missing(symbol, *args)
        if args.empty?
          if key?(symbol)
            self[symbol]
          elsif key?(symbol.to_s)
            self[symbol.to_s]
          elsif auto_vivifiy_on_read?
            self[symbol] = Mash.new
            self[symbol]
          else
            raise ArgumentError, "Attribute #{symbol} is not defined!" unless auto_vivifiy_on_read
          end
        else
          key_to_set = symbol.to_s[/^(.+)=$/, 1] || symbol
          self[key_to_set] = (args.length == 1 ? args[0] : args)
        end
      end