dvd6_2.sol

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

...

contract SimpleGovernance {

...
    struct GovernanceAction {
        address receiver;
        bytes data;
        uint256 weiAmount;
        uint256 proposedAt;
        uint256 executedAt;
    }
...
    
    uint256 private ACTION_DELAY_IN_SECONDS = 2 days;

...
    function queueAction(address receiver, bytes calldata data, uint256 weiAmount) external returns (uint256) {
        require(_hasEnoughVotes(msg.sender), "Not enough votes to propose an action");
        require(receiver != address(this), "Cannot queue actions that affect Governance");

        uint256 actionId = actionCounter;

        GovernanceAction storage actionToQueue = actions[actionId];
        actionToQueue.receiver = receiver;
        actionToQueue.weiAmount = weiAmount;
        actionToQueue.data = data;
        actionToQueue.proposedAt = block.timestamp;

        actionCounter++;

        emit ActionQueued(actionId, msg.sender);
        return actionId;
    }

    function executeAction(uint256 actionId) external payable {
        require(_canBeExecuted(actionId), "Cannot execute this action");
        
        GovernanceAction storage actionToExecute = actions[actionId];
        actionToExecute.executedAt = block.timestamp;

        actionToExecute.receiver.functionCallWithValue(
            actionToExecute.data,
            actionToExecute.weiAmount
        );

        emit ActionExecuted(actionId, msg.sender);
    }

    function getActionDelay() public view returns (uint256) {
        return ACTION_DELAY_IN_SECONDS;
    }

    /**
     * @dev an action can only be executed if:
     * 1) it's never been executed before and
     * 2) enough time has passed since it was first proposed
     */
    function _canBeExecuted(uint256 actionId) private view returns (bool) {
        GovernanceAction memory actionToExecute = actions[actionId];
        return (
            actionToExecute.executedAt == 0 &&
            (block.timestamp - actionToExecute.proposedAt >= ACTION_DELAY_IN_SECONDS)
        );
    }
    
    function _hasEnoughVotes(address account) private view returns (bool) {
        uint256 balance = governanceToken.getBalanceAtLastSnapshot(account);
        uint256 halfTotalSupply = governanceToken.getTotalSupplyAtLastSnapshot() / 2;
        return balance > halfTotalSupply;
    }
}