diff --git a/lib/ransack/search.rb b/lib/ransack/search.rb
index d92ba939c..e1ae083d6 100644
--- a/lib/ransack/search.rb
+++ b/lib/ransack/search.rb
@@ -152,7 +152,7 @@ def sanitized_scope_args(args)
     end
 
     def collapse_multiparameter_attributes!(attrs)
-      attrs.keys.each do |k|
+      attrs.each_key do |k|
         if k.include?(Constants::LEFT_PARENTHESIS)
           real_attribute, position = k.split(/\(|\)/)
           cast =