     @static
     @return {String} propName
     ###
+    @_propOfCreatedAt: undefined 
     @getPropOfCreatedAt: ->
 
         if @_propOfCreatedAt is undefined

    @static
    @return {String} propName
    ###
    @getPropOfUpdatedAt: ->

        if @_propOfUpdatedAt is undefined

    @static
    @return {Array}
    ###
    @_modelProps: undefined
    @getModelProps: ->

        if not @_modelProps?
