wip #4804

diff --git a/src/Document.php b/src/Document.php
index c539ec8ddb1cddd9d36774d0ea980b3e21f146bb..6363084f3a54edfef043594198ff7430d224f026 100644 (file)
--- a/src/Document.php
+++ b/src/Document.php
@@ -145,11 +145,13 @@ class Document
     }
 
     /**
-     * @param string|array $keywords
+     * @param string|array|null $keywords
      */
-    public function setKeywords(string|array $keywords): void
+    public function setKeywords(string|array|null $keywords): void
     {
-        if (is_array($keywords)) {
+        if(null===$keywords){
+            $keywords='';
+        }else        if (is_array($keywords)) {
             $keywords = implode(' ', $keywords);
         }
         $this->keywords = $keywords;