# File lib/aws/simple_db/item_collection.rb, line 573
      def replace_placeholders(str, *substitutions)
        named = {}
        named = substitutions.pop if substitutions.last.kind_of?(Hash)
        if str =~ /['"`]/
          count = 0
          str = str.scan(OUTSIDE_QUOTES_REGEX).
            map do |(before, quoted, after)|

            (before, after) = [before, after].map do |s|
              s, count =
                replace_placeholders_outside_quotes(s, count, substitutions, named)
              s
            end
            [before, quoted, after].join
          end.join
        else
          # no quotes
          str, count =
            replace_placeholders_outside_quotes(str, 0, substitutions, named)
        end
        raise ArgumentError.new("extra value(s): #{substitutions.inspect}") unless
          substitutions.empty?
        str
      end