add static method to get inherited class querybuilder from model, add isset method in model

src/Model.php

@@ -121,6 +121,21 @@ class Model
         }
     }
 
+    public function __isset($name): bool
+    {
+        if (method_exists($this, $name)) {
+            return true;
+        } else {
+            return isset($this->values[$name]);
+        }
+    }
+
+    public static function q(): QueryBuilder
+    {
+        $ist = new static();
+        return $ist->newQueryBuilder();
+    }
+
     public function __get($name): mixed
     {
         if (isset($this->values[$name])) {