         return @$markings if arguments.length is 0
         noMarkings = "the markings should be a object"
         assert _.isObject(markings), noMarkings
-        _.extend (@$markings ?= {}), markings
+        assert _.extend (@$markings ?= {}), markings
         @emit.call @, "markings", arguments...
         assert @$markings; return @$markings
 

        assert _.extend (@$schemas ?= {}), schemas
        @emit.call this, "schemas", arguments...
        assert @$schemas; return @$schemas

            reasoning: reasoning
            code: code

    # Either get or set the relevant information of the method that
    # is being described by this document. If you do no supply any
    # arguments this method will return already described failures.
