code: function walk(o, f, n, s) {
        s = s || this;
  
        if (o) {
          if (n) {
            o = o[n];
          }
  
          Arr.each(o, function (o, i) {
            if (f.call(s, o, i, n) === false) {
              return false;
            }
  
            walk(o, f, n, s);
          });
        }
      }
docs: Executed the specified function for each item in a object tree.
  
  @method walk
  @param {Object} o Object tree to walk though.
  @param {function} f Function to call for each item.
  @param {String} n Optional name of collection inside the objects to walk for example childNodes.
  @param {String} s Optional scope to execute the function in.