Add DBS mutation class to an annotated DBS VCF
AddDBSClass(vcf)The original vcf with three additional columns
DBS78.class, DBS136.class and DBS144.class added.
An in-memory VCF file annotated with sequence context and
transcript information by function AnnotateDBSVCF. It must
*not* contain indels and must *not* contain SBS (single base
substitutions), or triplet base substitutions etc.