SAML2\AuthnRequest::parseRequestedAuthnContext PHP Method

    protected function parseRequestedAuthnContext(\DOMElement $xml)
    {
        $requestedAuthnContext = Utils::xpQuery($xml, './saml_protocol:RequestedAuthnContext');
        if (empty($requestedAuthnContext)) {
            return;
        }
        $requestedAuthnContext = $requestedAuthnContext[0];
        $rac = array('AuthnContextClassRef' => array(), 'Comparison' => Constants::COMPARISON_EXACT);
        $accr = Utils::xpQuery($requestedAuthnContext, './saml_assertion:AuthnContextClassRef');
        foreach ($accr as $i) {
            $rac['AuthnContextClassRef'][] = trim($i->textContent);
        }
        if ($requestedAuthnContext->hasAttribute('Comparison')) {
            $rac['Comparison'] = $requestedAuthnContext->getAttribute('Comparison');
        }
        $this->requestedAuthnContext = $rac;
    }