code: public Fastq build()
  	{
  		if (description == null)
  		{
  			throw new IllegalStateException("description must not be null");
  		}
  		if (sequence == null)
  		{
  			throw new IllegalStateException("sequence must not be null");
  		}
  		if (quality == null)
  		{
  			throw new IllegalStateException("quality must not be null");
  		}
  		if (!sequenceAndQualityLengthsMatch())
  		{
  			throw new IllegalStateException("sequence and quality scores must be the same length");
  		}
  		Fastq fastq = new Fastq(description, sequence.toString(), quality.toString(), variant);
  		return fastq;
  	}
docs: Build and return a new FASTQ formatted sequence configured from the properties of this builder.
  
  @return a new FASTQ formatted sequence configured from the properties of this builder
  @throws IllegalStateException if the configuration of this builder results in an illegal state