```\nFile: ProxyFactory.sol\n    function setContest(address organizer, bytes32 contestId, uint256 closeTime, address implementation)\n        public\n        onlyOwner\n// rest of code\n// rest of code\n        bytes32 salt = _calculateSalt(organizer, contestId, implementation);\n        if (saltToCloseTime[salt] != 0) revert ProxyFactory__ContestIsAlreadyRegistered();\n        saltToCloseTime[salt] = closeTime;\n```\n