diff --git a/src/Credentials/GCECredentials.php b/src/Credentials/GCECredentials.php
index a0f759dc4..8beb10c9e 100644
--- a/src/Credentials/GCECredentials.php
+++ b/src/Credentials/GCECredentials.php
@@ -449,20 +449,20 @@ public function getCacheKey()
     }
 
     /**
-     * @return array{access_token:string,expires_at:int}|null
+     * @return array{access_token:string,expires_at:int}|array{id_token:string}|null
      */
     public function getLastReceivedToken()
     {
         if ($this->lastReceivedToken) {
             if (array_key_exists('id_token', $this->lastReceivedToken)) {
                 return [
-                    'id_token' => $this->lastReceivedToken['id_token'],
+                    'id_token' => $this->lastReceivedToken['id_token']
                 ];
             }
 
             return [
                 'access_token' => $this->lastReceivedToken['access_token'],
-                'expires_at' => $this->lastReceivedToken['expires_at'],
+                'expires_at' => $this->lastReceivedToken['expires_at']
             ];
         }