function _cancelAuction(uint256 _tokenId) internal {
    Auction storage _auction = tokenIdToAuction[_tokenId];
    require(_auction.seller == msg.sender || msg.sender == owner);
    emit CancelAuction(_auction.id, _auction.seller, _tokenId);
    _cancelEscrow(_auction.seller, _tokenId);
    delete tokenIdToAuction[_tokenId];
  }