docs: function flattenHead(obj) {
      var newHead = [];
  
      _arrayCopy(newHead, obj["head-start"]);
      _arrayCopy(newHead, obj["head"]);
      _arrayCopy(newHead, obj["head-end"]);
  
      delete obj["head-start"];
      delete obj["head-end"];
      obj.head = newHead;
  
      return obj;
  }