diff --git a/danceschool/core/forms.py b/danceschool/core/forms.py
index <HASH>..<HASH> 100644
--- a/danceschool/core/forms.py
+++ b/danceschool/core/forms.py
@@ -75,7 +75,7 @@ class CheckboxSelectMultipleWithDisabled(CheckboxSelectMultiple):
     To make an option part of a separate "override" choice set, add a dictionary key {'override': True}
     """
 
-    def render(self, name, value, attrs=None, choices=()):
+    def render(self, name, value, attrs=None, choices=(), renderer=None):
         if value is None:
             value = []
         has_id = attrs and 'id' in attrs
Added renderer option for Django <I>+ compatibility