code: static String convertQualities(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.getQuality();
  		}
  		int size = fastq.getQuality().length();
  		double[] errorProbabilities = errorProbabilities(fastq, new double[size]);
  		StringBuilder sb = new StringBuilder(size);
  		for (int i = 0; i < size; i++)
  		{
  			sb.append(variant.quality(variant.qualityScore(errorProbabilities[i])));
  		}
  		return sb.toString();
  	}
docs: Convert the qualities in 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 qualities in the specified FASTQ formatted sequence converted to the
  specified FASTQ sequence format variant