phpstan level 1 errors reduction

homepage/participo/lib/participoLib/event.php

@@ -10,7 +10,7 @@ class Event
     // members in the db
     private $id = null; //< unique id of the event in the db
     private $date = null; //< date for the event (@todo ranges?)
-    private $shiaiId = null; //< unique id of the shiai in the db (if appropriate)
+    private ?int $shiaiId = null; //< unique id of the shiai in the db (if appropriate)
     private $deadline = null; //< until when one can register for the event
     private $remarks = null; //< remarks to the event (special rules) or a json object for missing data (e.g. non-shiai events)
 
@@ -59,7 +59,7 @@ class Event
      *
      * @return int>0 id for the shiai in the db
      */
-    public function getShiaiId()
+    public function getShiaiId(): ?int
     {
         return $this->shiaiId;
     }