code: public static PermutationChromosome<Integer>
  	ofInteger(final int start, final int end) {
  		if (end <= start) {
  			throw new IllegalArgumentException(format(
  				"end <= start: %d <= %d", end, start
  			));
  		}
  
  		return ofInteger(IntRange.of(start, end), end - start);
  	}
docs: Create an integer permutation chromosome with the given range.
  
  @since 2.0
  
  @param start the start of the integer range (inclusively) of the returned
  chromosome.
  @param end the end of the integer range (exclusively) of the returned
  chromosome.
  @return a integer permutation chromosome with the given integer range
  values.
  @throws IllegalArgumentException if {@code start >= end} or
  {@code start <= 0}