Dev: fix array_keys() expects parameter 1 to be array, object given /application/helpers/expressions/em_manager_helper.php(3473)
Dev: put attributes array in $_SESSION['survey_'.$surveyid]['thistoken']
Dev: @samMousa : see comment https://github.com/LimeSurvey/LimeSurvey/commit/0f17969ad677149d2994db5295bb388ef606d6b3#commitcomment-4139555
Dev: please, review, seems fixed, but maybe add a new function in model (to use static and cache) is a good idea