private PEltype merge(Slice<PEltype> slice) { PEltype p = copy(slice.getContents().stream() .findFirst() .orElseThrow(() -> new ConvertException("At least one <p> must exist for content."))); p.setBegin(ConversionHelper.msToSmpteTimecode(slice.getBegin(), frameRate)); p.setEnd(ConversionHelper.msToSmpteTimecode(slice.getEnd(), frameRate)); p.getContent().clear(); p.getContent().addAll(mergeContent(slice.getContents())); return p; }