private CharSequence renderRoleSet(Set<String> roles) {
        boolean first = true;
        StringBuilder sb = new StringBuilder();
        for (String role : roles) {
            if (first) {
                first = false;
            } else {
                sb.append(" or ");
            }
            sb.append("\u201Crole=");
            sb.append(role);
            sb.append('\u201D');
        }
        return sb;
    }
@see nu.validator.checker.Checker#characters(char[], int, int)
src/nu/validator/checker/schematronequiv/Assertions.java