fix for BIESt #971

Closes #971

Merge request studip/studip!578

1 files changed, 5 insertions, 4 deletions

diff --git a/lib/classes/SeminarCategories.class.php b/lib/classes/SeminarCategories.class.php
index fdb955e..5302f1e 100644
--- a/lib/classes/SeminarCategories.class.php
+++ b/lib/classes/SeminarCategories.class.php
@@ -45,10 +45,11 @@ class SeminarCategories {
      * @param String $id
      * @return Array
      */
-    public static function Get($id){
-        if(is_null(self::$seminar_categories[$id])){
+    public static function Get($id)
+    {
+        if (empty(self::$seminar_categories[$id])) {
             $cat = new SeminarCategories($id);
-            if($cat->id !== false) {
+            if ($cat->id !== false) {
                 self::$seminar_categories[$id] = $cat;
             } else {
                 self::$seminar_categories[$id] = false;
@@ -134,4 +135,4 @@ class SeminarCategories {
         }
     }
 }
-?>
\ No newline at end of file
+?>