  function notifyRewardAmount(address token, uint amount) external lock {
      require(amount > 0);
      if (!isReward[token]) {
        require(rewards.length < MAX_REWARD_TOKENS, "too many rewards tokens");
      }
      // bribes kick in at the start of next bribe period
      uint adjustedTstamp = getEpochStart(block.timestamp);
      uint epochRewards = tokenRewardsPerEpoch[token][adjustedTstamp];

      _safeTransferFrom(token, msg.sender, address(this), amount);
      tokenRewardsPerEpoch[token][adjustedTstamp] = epochRewards + amount;

      if (!isReward[token]) {
          isReward[token] = true;
          rewards.push(token);
          IGauge(gauge).addBribeRewardToken(token);
      }

      emit NotifyReward(msg.sender, token, adjustedTstamp, amount);
  }
    function deliverBribes() external lock {
        require(msg.sender == voter);
        IBribe sb = IBribe(bribe);
        uint bribeStart = block.timestamp - (block.timestamp % (7 days)) + BRIBE_LAG;
        uint numRewards = sb.rewardsListLength();

        for (uint i = 0; i < numRewards; i++) {
            address token = sb.rewards(i);
            uint epochRewards = sb.deliverReward(token, bribeStart);
            if (epochRewards > 0) {
                _notifyBribeAmount(token, epochRewards, bribeStart);
            }
        }
    }
    function distribute(address _gauge) public lock {
        require(isAlive[_gauge]); // killed gauges cannot distribute
        uint dayCalc = block.timestamp % (7 days);
        require((dayCalc < BRIBE_LAG) || (dayCalc > (DURATION + BRIBE_LAG)), "cannot claim during votes period");
        IMinter(minter).update_period();
        _updateFor(_gauge);
        uint _claimable = claimable[_gauge];
        if (_claimable > IGauge(_gauge).left(base) && _claimable / DURATION > 0) {
            claimable[_gauge] = 0;
            IGauge(_gauge).notifyRewardAmount(base, _claimable);
            emit DistributeReward(msg.sender, _gauge, _claimable);
            // distribute bribes & fees too
            IGauge(_gauge).deliverBribes();
        }
    }
    function getReward(address account, address[] memory tokens) external lock {
        require(msg.sender == account || msg.sender == voter);
        _unlocked = 1;
        IVoter(voter).distribute(address(this));
        _unlocked = 2;

        for (uint i = 0; i < tokens.length; i++) {
            (rewardPerTokenStored[tokens[i]], lastUpdateTime[tokens[i]]) = _updateRewardPerToken(tokens[i]);

            uint _reward = earned(tokens[i], account);
            lastEarn[tokens[i]][account] = block.timestamp;
            userRewardPerTokenStored[tokens[i]][account] = rewardPerTokenStored[tokens[i]];
            if (_reward > 0) _safeTransfer(tokens[i], account, _reward);

            emit ClaimRewards(msg.sender, tokens[i], _reward);
        }

        uint _derivedBalance = derivedBalances[account];
        derivedSupply -= _derivedBalance;
        _derivedBalance = derivedBalance(account);
        derivedBalances[account] = _derivedBalance;
        derivedSupply += _derivedBalance;

        _writeCheckpoint(account, derivedBalances[account]);
        _writeSupplyCheckpoint();
    }
