code: function(fn, all) {
          return Y.one(Y_DOM.elementByAxis(this._node, 'previousSibling', _wrapFn(fn), all));
      }
docs: Returns the previous matching sibling.
  Returns the nearest element node sibling if no method provided.
  @method previous
  @param {String | Function} fn A selector or boolean method for testing elements.
  If a function is used, it receives the current node being tested as the only argument.
  @return {Node} Node instance or null if not found