.add_property("start", &SeqSpan::start, &SeqSpan::setStart,
"start position relative to root sequence")
.add_property("stop", &SeqSpan::stop, &SeqSpan::setStop,
.add_property("start", &SeqSpan::start, &SeqSpan::setStart,
"start position relative to root sequence")
.add_property("stop", &SeqSpan::stop, &SeqSpan::setStop,