protected function getClassAttribute($value, &$classesCheck)
{
$statements = $this->createStatements($value);
$value = is_array($statements[0]) ? $statements[0][0] : $statements[0];
$classesCheck[] = '(is_array($_a = ' . $value . ') ? implode(" ", $_a) : $_a)';
return $this->keepNullAttributes ? '' : 'null';
}