jquery extend slide show/hide

jQuery extends sliding.js

jQuery.fn.extend({
  slideRightShow: function(duration) {
    return this.each(function() {
        $(this).show('slide', {direction: 'right'}, duration);
    });
  },
  slideLeftHide: function(duration) {
    return this.each(function() {
      $(this).hide('slide', {direction: 'left'}, duration);
    });
  },
  slideRightHide: function(duration) {
    return this.each(function() {
      $(this).hide('slide', {direction: 'right'}, duration);
    });
  },
  slideLeftShow: function(duration) {
    return this.each(function() {
      $(this).show('slide', {direction: 'left'}, duration);
    });
  }
});