validate_internal

# File lib/net/imap.rb, line 1633
      def validate_internal(data)
        case data
        when "*"
        when Integer
          NumValidator.ensure_nz_number(data)
        when Range
        when Array
          data.each do |i|
            validate_internal(i)
          end
        when ThreadMember
          data.children.each do |i|
            validate_internal(i)
          end
        else
          raise DataFormatError, data.inspect
        end
      end