private function getNamesList($names)
{
$attributes = NULL;
if (is_array($names)) {
$attributes = $names;
} elseif (is_string($names) && $names !== '*' && $names !== '') {
$attributes = array($names);
} elseif (isset($names) && $names !== '*') {
throw new \InvalidArgumentException();
}
return $attributes;
}