code: public Variant createFromTemplate(Variant target) {
          Variant var = new Variant(target.getChromosome(), target.getStart(), target.getEnd(), target.getReference(), target.getAlternate());
          var.setType(target.getType());
          for(StudyEntry tse : target.getStudies()){
              StudyEntry se = new StudyEntry(tse.getStudyId());
              se.setFiles(Collections.singletonList(new FileEntry("", "", new HashMap<>())));
              se.setFormat(Arrays.asList(getGtKey(), getFilterKey()));
              se.setSamplesPosition(new HashMap<>());
              se.setSamplesData(new ArrayList<>());
              var.addStudyEntry(se);
          }
          return var;
      }
docs: Create an empty Variant (position, ref, alt) from a template with basic Study information without samples.
  @param target Variant to take as a template
  @return Variant filled with chromosome, start, end, ref, alt, study ID and format set to GT only, BUT no samples.