code: func (l *logger) SetDebug(facility string, enabled bool) {
  	l.mut.Lock()
  	defer l.mut.Unlock()
  	if _, ok := l.debug[facility]; enabled && !ok {
  		l.SetFlags(DebugFlags)
  		l.debug[facility] = struct{}{}
  	} else if !enabled && ok {
  		delete(l.debug, facility)
  		if len(l.debug) == 0 {
  			l.SetFlags(DefaultFlags)
  		}
  	}
  }
docs: // SetDebug enabled or disables debugging for the given facility name.