diff --git a/active_event/lib/active_event/domain.rb b/active_event/lib/active_event/domain.rb
index <HASH>..<HASH> 100644
--- a/active_event/lib/active_event/domain.rb
+++ b/active_event/lib/active_event/domain.rb
@@ -34,7 +34,7 @@ module ActiveEvent
         base.server_uri = 'druby://127.0.0.1:8787'
       end
 
-      def set_config(protocol: 'druby', host: 'localhost', port: 8787)
+      def set_config(protocol = 'druby', host = 'localhost', port = 8787)
         self.server_uri = "#{protocol}://#{host}:#{port}"
       end
     end
diff --git a/active_event/lib/active_event/support/attr_setter.rb b/active_event/lib/active_event/support/attr_setter.rb
index <HASH>..<HASH> 100644
--- a/active_event/lib/active_event/support/attr_setter.rb
+++ b/active_event/lib/active_event/support/attr_setter.rb
@@ -21,7 +21,7 @@ module ActiveEvent::Support
       def attributes(*args)
         super
         args.each do |attr|
-          define_method "#{attr}=", -> (value) { attributes[attr] = value }
+          define_method "#{attr}=", lambda { |value| attributes[attr] = value }
         end
       end
     end
* different syntax for lambda and default args to ensure rubinius support