remove unused attributes() boilerplate

lib/virtual/type.rb

@@ -33,9 +33,7 @@ module Virtual
       @clazz = clazz
     end
     attr_accessor :clazz
-    def attributes
-      [:clazz]
-    end
+
     def at_index block , left , right
       block.ldr( self , left , right )
       self
@@ -48,9 +46,6 @@ module Virtual
   class Mystery < Type
     def initialize 
     end
-    def attributes
-      []
-    end
     def as type
       type.new
     end