function checkinSpeaker(uint256 _talkId)
        external
        onlyOwner
        duringEvent
    {
        require(speakersTalks[_talkId].checkedIn == false);
        require(speakersTalks[_talkId].status == ApplicationStatus.Accepted);
        
        uint256 bidId = totalSupply();
        super._mint(msg.sender, bidId);
        speakersTalks[_talkId].checkedIn = true;
    }