protected static function arrayOnlyContainsScalars(array $array) {
$result = TRUE;
foreach ($array as $element) {
if (is_array($element)) {
$result = self::arrayOnlyContainsScalars($element);
}
else {
if (!is_scalar($element) && !is_null($element)) {
$result = FALSE;
}
}
if ($result === FALSE) {
break;
}
}
return $result;
}