docs: public void increment(int level) {
  		assert level >= 1;
  		if (this.numbers.size() < level) {
  			do {
  				this.numbers.addLast(0);
  			} while (this.numbers.size() < level);
  		} else if (this.numbers.size() > level) {
  			do {
  				this.numbers.removeLast();
  			} while (this.numbers.size() > level);
  		}
  		assert this.numbers.size() == level;
  		final int previousSection = this.numbers.removeLast();
  		this.numbers.addLast(previousSection + 1);
  	}