protected GenomicRegionsBuilder generateRegions() throws Exception{
GenomicRegionsBuilder gbout= new GenomicRegionsBuilder();
xxx= new GenomicRegionsBuilder();
ArrayList<GenomicRegion> al= gb.getAllGenomicRegions();
RandomObject<GenomicRegion> rand= new RandomObject( al, null);
HashSet<GenomicRegion> set= new HashSet<>();
while(set.size()<n){
GenomicRegion reg= rand.randomObject();
if(!set.contains(reg)){
set.add(reg);
}
}