How to use standard symbols in NSMenu?

Reffering to Apple'S HIG on开发者_如何转开发 Menu, "Using Symbols in Menu" http://developer.apple.com/mac/library/DOCUMENTATION/UserExperience/Conceptual/AppleHIGuidelines/XHIGMenus/XHIGMenus.html#//apple_ref/doc/uid/TP30000356-TPXREF125

How do I use those standard symbols for my menu itmes? Well I just need example code or some example to get started.

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In interface builder, select a Menu Item. In the Menu Item Attributes of the Inspector you can then change its "On Image", "Off Image", and "Mix Image". Some of the images mentioned in the HIG will be prefixed NSMenu, for instance NSMenuCheckmark and NSMenuMixedState. You'd then enable this image by using the NSMenuItem's setState: method.