code: public void setLevels(Level minLevel, Level maxLevel) throws IllegalArgumentException {
          if (minLevel != null && maxLevel != null && minLevel.intValue() > maxLevel.intValue()) {
              throw new IllegalArgumentException("Value of the minLevel parameter should specify level not larger than the value of the maxLevel parametere.");
          }
          this.minLevel = minLevel;
          this.maxLevel = maxLevel;
      }
docs: sets the current value for the minimum and maximum levels
  
  @param minLevel minimum level
  @throws IllegalArgumentException if minLevel is bigger than maxLevel