@Override
	public boolean isValid() {
		byte valid = _valid;
		if (valid == -1) {
			valid = (byte)(_chromosomes.forAll(Verifiable::isValid) ? 1 : 0);
			_valid = valid;
		}

		return _valid == 1;
	}
Test if this genotype is valid. A genotype is valid if all its
{@link Chromosome}s are valid.

@return true if this genotype is valid, false otherwise.
jenetics/src/main/java/io/jenetics/Genotype.java