code: public static Fastq convert(final Fastq fastq, final FastqVariant variant)
  	{
  		if (fastq == null)
  		{
  			throw new IllegalArgumentException("fastq must not be null");
  		}
  		if (variant == null)
  		{
  			throw new IllegalArgumentException("variant must not be null");
  		}
  		if (fastq.getVariant().equals(variant))
  		{
  			return fastq;
  		}
  		return new Fastq(fastq.getDescription(), fastq.getSequence(), convertQualities(fastq, variant), variant);
  	}
docs: Convert the specified FASTQ formatted sequence to the
  specified FASTQ sequence format variant.
  
  @since 4.2
  @param fastq FASTQ formatted sequence, must not be null
  @param variant FASTQ sequence format variant, must not be null
  @return the specified FASTQ formatted sequence converted to the
  specified FASTQ sequence format variant