function releaseFor(address _beneficiary, uint256 _id) public onlyWhenActivated onlyValidTokenTimelock(_beneficiary, _id) {
    TokenTimelock storage tokenLock = tokenTimeLocks[_beneficiary][_id];
    require(!tokenLock.released);
    
    require(block.timestamp >= tokenLock.releaseTime);
    tokenLock.released = true;
    require(token.transfer(_beneficiary, tokenLock.amount));
    emit TokenTimelockReleased(_beneficiary, tokenLock.amount);
  }