RenPy Labels

def show_labels(prefix = u""):
    labels = [
        lbn
        for lbn in renpy.get_all_labels().get_rollback()
        if lbn.lower().startswith(prefix)
        ]
    xadjustment = ui.adjustment()
    yadjustment = ui.adjustment()
    while True:
        ui.frame()
        ui.vbox()
        layout.label(_(u"Labels which starts with " + prefix), None)
        ui.textbutton(_(u"Close"), clicked=ui.returns(False), size_group="labels")
        ui.side(['c', 'b', 'r'], spacing=5)
        vp = ui.viewport(xadjustment=xadjustment, yadjustment=yadjustment, mousewheel=True)
        ui.vbox()
        for lbn in labels:
            ui.button(clicked=ui.returns(lbn), size_group="labels", xminimum=1.0)
            ui.text(lbn, style="button_text", xalign=0.0)
        ui.close()
        ui.bar(adjustment=xadjustment, style='scrollbar')
        ui.bar(adjustment=yadjustment, style='vscrollbar')
        ui.close()
        ui.close()
        rv = ui.interact()
        if rv is False:
            return
        renpy.jump(rv)