protected function getHumanReadableIndicatorValues($rules)
    {
        // No processing needed for blank rule:
        if ($rules == 'blank') {
            return $rules;
        }

        // Create string:
        $string = '';
        $length = strlen($rules);
        for ($i = 0; $i < $length; $i++) {
            $current = substr($rules, $i, 1);
            if ($current == 'b') {
                $current = 'blank';
            }
            $string .= $current;
            if ($length - $i == 2) {
                $string .= ' or ';
            } else if ($length - $i > 2) {
                $string .= ', ';
            }
        }

        return $string;
    }