diff --git a/src/Providers/Theme.php b/src/Providers/Theme.php
index 67d280c..dca70b4 100644
--- a/src/Providers/Theme.php
+++ b/src/Providers/Theme.php
@@ -37,11 +37,16 @@ public function custom($name, $data)
 		$this->customData[$name] = $data;
 
 		if (method_exists($this, 'custom_' . $name)) {
-			$function = new \Twig_SimpleFunction($name, [$this, 'custom_' . $name], ['is_safe' => ['html']]);
-			$this->theme->addFunction($function);
+			$this->addFunction($name, $this);
 		}
 	}
 
+	public function addFunction($name, $obj)
+	{
+		$function = new \Twig_SimpleFunction($name, [$obj, 'custom_' . $name], ['is_safe' => ['html']]);
+		$this->theme->addFunction($function);
+	}
+
 	public function custom_baun_nav()
 	{
 		$data = $this->customData['baun_nav'];