# File lib/aws/record/validator.rb, line 170
      def ensure_type type_or_types, *keys

        types = Array(type_or_types)

        keys.each do |key|

          next unless options.has_key?(key)
          next unless types.none?{|type| options[key].is_a?(type) }

          expected = types.map{|type| type.to_s }
          if expected.count == 1
            raise ArgumentError, "expected option :#{key} to be a #{expected}"
          else
            msg = "expected :#{key} to be one of #{expected.join(', ')}"
            raise ArgumentError, msg
          end

        end
      end