diff --git a/lib/assertion/dsl/attributes.rb b/lib/assertion/dsl/attributes.rb
index <HASH>..<HASH> 100644
--- a/lib/assertion/dsl/attributes.rb
+++ b/lib/assertion/dsl/attributes.rb
@@ -39,7 +39,8 @@ module Assertion
 
       def __add_attribute__(name)
         __check_attribute__(name)
-        attributes << define_method(name) { attributes[name] }
+        define_method(name) { attributes[name] }
+        attributes << name.to_sym
       end
 
       def __check_attribute__(name)
[BUG FIX] Fix incompatibility to rubies <I>- syntax