code: function (key, before) {                                           // 168
      var self = this;                                                             // 169
      var elt = self._dict[self._k(key)];                                          // 170
      var eltBefore = before ? self._dict[self._k(before)] : null;                 // 171
      if (elt === undefined)                                                       // 172
        throw new Error("Item to move is not present");                            // 173
      if (eltBefore === undefined) {                                               // 174
        throw new Error("Could not find element to move this one before");         // 175
      }                                                                            // 176
      if (eltBefore === elt.next) // no moving necessary                           // 177
        return;                                                                    // 178
      // remove from its old place                                                 // 179
      self._linkEltOut(elt);                                                       // 180
      // patch into its new place                                                  // 181
      elt.next = eltBefore;                                                        // 182
      self._linkEltIn(elt);                                                        // 183
    }
docs: 167