diff --git a/lib/active_flag/value.rb b/lib/active_flag/value.rb
index e5269ff..9030f30 100644
--- a/lib/active_flag/value.rb
+++ b/lib/active_flag/value.rb
@@ -48,8 +48,8 @@ def unset?(key)
     end
 
     def method_missing(symbol, *args, &block)
-      if key = symbol.to_s.chomp!('?') and @definition.keys.include?(key.to_sym)
-        set?(key.to_sym)
+      if key = symbol.to_s.chomp('?').to_sym and @definition.keys.include?(key)
+        set?(key)
       else
         super
       end