code: function(el, oldClassName, newClassName) {
              return Y.Dom.batch(el, Y.Dom._replaceClass, { from: oldClassName, to: newClassName });
          }
docs: Replace a class with another class for a given element or collection of elements.
  If no oldClassName is present, the newClassName is simply added.
  @method replaceClass
  @param {String | HTMLElement | Array} el The element or collection to remove the class from
  @param {String} oldClassName the class name to be replaced
  @param {String} newClassName the class name that will be replacing the old class name
  @return {Boolean | Array} A pass/fail boolean or array of booleans