How to remove a method of a widget ?

How to remove a method of a widget ?

Hi,

I'd like something simple I guess but I dunno how to do it. It's for the Accordion widget but it's the some for all widget.
Well, I'd like to destroy the  _keydown method.

  1. $.widget( "ui.accordion", {
  2.       _keydown: function( event ) {
  3.             // blah
  4.       },
  5.       // reblah
  6. });
Well I want to kill it because I already have the keys UP and DOWN used for the navigation, it breaks it :(

Thanks.