diff --git a/CloudObjects/SDK/ObjectRetriever.php b/CloudObjects/SDK/ObjectRetriever.php
index 80eb844..8ac6eb0 100644
--- a/CloudObjects/SDK/ObjectRetriever.php
+++ b/CloudObjects/SDK/ObjectRetriever.php
@@ -206,7 +206,7 @@ class ObjectRetriever implements CustomCacheAndLogInterface {
 	/**
 	 * Get an object description and return a CloudObject.
 	 */
-	public function getCloudObject(IRI $coid) : CloudObject {
+	public function getCloudObject(IRI $coid) : ?CloudObject {
 		$node = $this->getObjectNode($coid);
 		if (!$node) {
 			// Object not found
@@ -239,7 +239,7 @@ class ObjectRetriever implements CustomCacheAndLogInterface {
 	 * @param IRI $coid COID of the object
 	 * @return Node|null
 	 */
-	public function getObjectNode(IRI $coid) : Node {
+	public function getObjectNode(IRI $coid) : ?Node {
 		if (!COIDParser::isValidCOID($coid))
 			throw new Exception("Not a valid COID.");