Manager::isEqual

private function isEqual(Collection $collectionA, Collection $collectionB)
{
	$productIdsFromCollectionA = $this->getProductIdsFromCollection($collectionA);
	$productIdsFromCollectionB = $this->getProductIdsFromCollection($collectionB);

	return
		!array_diff($productIdsFromCollectionA, $productIdsFromCollectionB) &&
		!array_diff($productIdsFromCollectionB, $productIdsFromCollectionA)
	;
}