filter.append(SELECTOR_END);
filter.append(Conventions.SELECTOR_END);
    public String getFilterSuffix(int n) {        if ((n<0) || (n > size())) {            throw new IllegalArgumentException("Imposible to obtain filter fragment for n="+n);        }        if (n==0) {            return "";        }        StringBuffer filter = new StringBuffer();        for (int i = 0; i < n; i++) {            filter.append(SELECTOR_START);            filter.append(selectors[i]);            filter.append(SELECTOR_END);        }        return filter.toString();    }