diff --git a/src/Base/Objects/ApiObject.php b/src/Base/Objects/ApiObject.php
index 7790377..98d45e0 100644
--- a/src/Base/Objects/ApiObject.php
+++ b/src/Base/Objects/ApiObject.php
@@ -164,7 +164,7 @@ public static function getPropertyDataType(\ReflectionProperty $property): ?stdC
 
 		preg_match('/@var\s+(\w+)(\[])?/', $property->getDocComment(), $matches);
 
-		$o->class = $matches[1];
+		$o->class = isset($matches[1]) ? $matches[1] : null;
 		$o->isArray = isset($matches[2]);
 
         if ($o->class == null)