(severity: any2stringadd[Severity]).+(other)
(severity: math.Ordered[Severity]).<(that)
(severity: math.Ordered[Severity]).<=(that)
(severity: math.Ordered[Severity]).>(that)
(severity: math.Ordered[Severity]).>=(that)
(severity: math.Ordered[Severity]).compare(that)
(severity: math.Ordered[Severity]).compareTo(that)