diff --git a/lib/validates_timeliness/extensions/multiparameter_handler.rb b/lib/validates_timeliness/extensions/multiparameter_handler.rb
index af2052f..a18c2b2 100644
--- a/lib/validates_timeliness/extensions/multiparameter_handler.rb
+++ b/lib/validates_timeliness/extensions/multiparameter_handler.rb
@@ -1,4 +1,4 @@
-ActiveRecord::AttributeAssignment::MultiparameterAttribute.class_eval do
+ActiveRecord::AttributeAssignment.class_eval do
   private
 
   # Yield if date values are valid