From 580d67464e547b6ea0b3baa9721bd1c7421b692d Mon Sep 17 00:00:00 2001
From: Juanfra Magrini <juanframagrini@gmail.com>
Date: Wed, 5 Sep 2018 15:44:53 -0300
Subject: [PATCH] fixed helper method nested_tree_nodes when the subtree is nil

---
 lib/rails_admin_nestable/helper.rb | 1 +
 1 file changed, 1 insertion(+)

diff --git a/lib/rails_admin_nestable/helper.rb b/lib/rails_admin_nestable/helper.rb
index 4503588..79310f1 100755
--- a/lib/rails_admin_nestable/helper.rb
+++ b/lib/rails_admin_nestable/helper.rb
@@ -1,6 +1,7 @@
 module RailsAdminNestable
   module Helper
     def nested_tree_nodes(tree_nodes = [])
+      return if tree_nodes.nil?
       tree_nodes.map do |tree_node, sub_tree_nodes|
         li_classes = 'dd-item dd3-item'