Prado\Web\UI\WebControls\TCaptcha::setTokenAlphabet PHP Method

    public function setTokenAlphabet($value)
    {
        if (strlen($value) < 2) {
            throw new TConfigurationException('captcha_tokenalphabet_invalid');
        }
        $this->setViewState('TokenAlphabet', $value, '234578adefhijmnrtABDEFGHJLMNRT');
    }