    RabbitHoleReceipt public rabbitholeReceiptContract;
function getRabbitholeReceiptContract() public view returns(RabbitHoleReceipt) {
    return rabbitHoleReceiptContract;
}
function mintReceipt(string memory questId_, bytes32 hash_, bytes memory signature_) public {
    ...
    RabbitHoleReceipt rabbitholeReceiptContract = Quest(quests[questId_].questAddress).getRabbitholeReceiptContract();
    rabbitholeReceiptContract.mint(msg.sender, questId_);
    ...
}
