code: func (l *LogAction) Log(level, format string, args ...interface{}) predicate.BoolPredicate {
  	return func() bool {
  		ilevel, err := log.ParseLevel(level)
  		if err != nil {
  			ilevel = log.DebugLevel
  		}
  		var writer io.Writer
  		if l.writer != nil {
  			writer = l.writer
  		} else {
  			writer = log.StandardLogger().WriterLevel(ilevel)
  		}
  		writer.Write([]byte(fmt.Sprintf(format, args...)))
  		return true
  	}
  }
docs: // Log logs with specified level and formatting string with arguments