function createSiringAuction(
        uint256 _ninjaId,
        uint256 _startingPrice,
        uint256 _endingPrice,
        uint256 _duration
    )
        external
        whenNotPaused
    {
        require(_owns(msg.sender, _ninjaId));
        require(isReadyToBreed(_ninjaId));
        _approve(_ninjaId, siringAuction);
        siringAuction.createAuction(
            _ninjaId,
            _startingPrice,
            _endingPrice,
            _duration,
            msg.sender
        );
    }