func: function unlock (uint256 _id) public {
          TokenTimeLockInfo memory lockInfo = locks [_id];
          delete locks [_id];
  
          require (lockInfo.amount > 0);
          require (lockInfo.unlockTime <= block.timestamp);
  
          emit Unlock (_id, lockInfo.beneficiary, lockInfo.amount, lockInfo.unlockTime);
  
          require (
              ISC.transfer (
                  lockInfo.beneficiary, lockInfo.amount));
      }