Как можно реализовать проверку на админа?

function is_admin($peer_id, $from_id){ // Проверка на админа v1.0
        $param = array(
            'peer_id' => $peer_id,
	    'access_token' => $this->token,
            'v' => '5.90'
        );

        $params = http_build_query($param);

        $resp = json_decode(file_get_contents("https://api.vk.com/method/messages.getConversationMembers?$params"));

        foreach($resp['response']['items'] as $key){
            if ($key['member_id'] == $from_id){
                if($key['admin_ids'] == $from_id){
                return 'admin';
                }elseif($key['owner_id'] == $from_id){
                    return 'owner';
                }elseif($key['admin_ids'] != $from_id){
                    return 'false';
                }
            }
        }
    }