    def validate_line(line)
      # A bare CR or LF is not allowed in RFC5321.
      if /[\r\n]/ =~ line
        raise ArgumentError, "A line must not contain CR or LF"
      end
    end
The software uses CRLF (carriage return line feeds) as a special element, e.g. to separate lines or records, but it does not neutralize or incorrectly neutralizes CRLF sequences from inputs.