diff --git a/demos/init-db.php b/demos/init-db.php
index 18eefb828e..0fa1acaf83 100644
--- a/demos/init-db.php
+++ b/demos/init-db.php
@@ -7,6 +7,7 @@
 use Atk4\Core\Factory;
 use Atk4\Data\Field;
 use Atk4\Data\Model;
+use Atk4\Data\Reference;
 use Atk4\Ui\Exception;
 use Atk4\Ui\Form;
 use Atk4\Ui\Table;
@@ -299,7 +300,7 @@ public function addField(string $name, $seed = []): Field
     }
 
     #[\Override]
-    public function hasOne(string $link, array $defaults = [])
+    public function hasOne(string $link, array $defaults): Reference
     {
         // TODO remove once HasOne reference can infer type from their model
         if (!isset($defaults['type'])) {
diff --git a/docs/multiline.md b/docs/multiline.md
index e346acb681..d4dce061f9 100644
--- a/docs/multiline.md
+++ b/docs/multiline.md
@@ -30,7 +30,7 @@ class User extends \Atk4\Data\Model
         $this->addField('firstname', ['type' => 'string']);
         $this->addField('lastname', ['type' => 'string']);
 
-        $this->containsMany('addresses', [Address::class, 'system' => false]);
+        $this->containsMany('addresses', ['model' => [Address::class], 'system' => false]);
     }
 }
 
@@ -81,7 +81,7 @@ class Email extends \Atk4\Data\Model
 
         $this->addField('email_address', ['type' => 'string']);
 
-        $this->hasOne('user_id', [User::class]);
+        $this->hasOne('user_id', ['model' => [User::class]]);
     }
 }
 
@@ -99,7 +99,7 @@ class User extends \Atk4\Data\Model
         $this->addField('firstname', ['type' => 'string']);
         $this->addField('lastname', ['type' => 'string']);
 
-        $this->hasMany('Emails', [Email::class]);
+        $this->hasMany('Emails', ['model' => [Email::class]]);
     }
 }
 ```