private Event getError(final RequestContext requestContext) {
        WebUtils.addErrorMessageToContext(requestContext, CasWebflowConstants.TRANSITION_ID_CAPTCHA_ERROR,
            CasWebflowConstants.TRANSITION_ID_CAPTCHA_ERROR);
        return getEventFactorySupport().event(this, CasWebflowConstants.TRANSITION_ID_CAPTCHA_ERROR);
    }
This is {@link ValidateCaptchaAction}.

@author Misagh Moayyed
@since 5.0.0
support/cas-server-support-captcha-core/src/main/java/org/apereo/cas/web/flow/ValidateCaptchaAction.java