public function setOrderBy(array $orderBy)
{
// Validate and force the case for the direction.
foreach ($orderBy as $attribute => $direction) {
if (!in_array(strtoupper($direction), self::ORDER)) {
throw new \InvalidArgumentException(sprintf('Order direction "%s" is invalid. Valid values are ASC and DESC', $direction));
}
$orderBy[$attribute] = strtoupper($direction);
}
$this->orderBy = $orderBy;
return $this;
}