public Element toElement(CashOffice cashOffice) {
    Element cashOfficeElement = new Element("cashOffice");
    List<Seance> seances = cashOffice.getSeances();
    for (Seance seance : seances) {
      Element seanceElement = new SeanceTranslator().toElement(seance);
      Element ticketsElement = new Element("tickets");
      List<Ticket> tickets = seance.getTicketsByCOid(cashOffice.getNumber());
      for (Ticket ticket : tickets) {
        ticketsElement.addContent(new TicketTranslator().toElement(ticket));
      }
      seanceElement.addContent(ticketsElement);
      cashOfficeElement.addContent(seanceElement);
    }
    cashOfficeElement.setAttribute("id", Integer.toString(cashOffice.getNumber()));
    return cashOfficeElement;
  }