function getRandomNumber(uint256 seed) public returns (bytes32 requestId) {
       return requestRandomness(keyHash, fee, seed);
   }

function fulfillRandomness(bytes32 requestId, uint256 randomness) internal override {
       randomResult = randomness;
   }

https://docs.chain.link/docs/intermediates-tutorial/

function getRandomNumber(uint256 seed) public returns (bytes32 requestId) {
       return requestRandomness(keyHash, fee, seed);
   }

function fulfillRandomness(bytes32 requestId, uint256 randomness) internal override {
       randomResult = randomness;
   }

https://docs.chain.link/docs/intermediates-tutorial/