diff --git a/qtpy/uic.py b/qtpy/uic.py
index 07d7a78..84525ab 100644
--- a/qtpy/uic.py
+++ b/qtpy/uic.py
@@ -181,7 +181,7 @@ else:
 
         custom_widget_classes = {}
 
-        for custom_widget in custom_widgets.getchildren():
+        for custom_widget in list(custom_widgets):
 
             cw_class = custom_widget.find('class').text
             cw_header = custom_widget.find('header').text