Random3-part1.sol

pragma solidity ^0.8.0;

contract RandomNumbers{
    uint256 public preparationBlockNumber;
    bool public canCallRandom;
    
    function prepareRandom() public {
        /**
        When called sets the preparation block number to the current block number.
         */
        require(!canCallRandom, "Already prepared.");
        // TODO: Commit the caller to random
        preparationBlockNumber = block.number;
        canCallRandom = true;
    }
}