# File lib/aws/dynamo_db/types.rb, line 79
      def type_indicator(value, context)
        case
        when value.kind_of?(DynamoDB::Binary) then :b
        when value.respond_to?(:to_str) then :s
        when value.kind_of?(Numeric) then :n
        when value.respond_to?(:each)
          indicator = nil
          value.each do |v|
            member_indicator = type_indicator(v, context)
            raise_error("nested collections", context) if
              member_indicator.to_s.size > 1
            raise_error("mixed types", context) if
              indicator and member_indicator != indicator
            indicator = member_indicator
          end
          indicator ||= :s
          "#{indicator}s""#{indicator}s"
        when value == :empty_number_set
          :ns
        else
          raise_error("unsupported attribute type #{value.class}", context)
        end
      end