function VestedPayment(
    uint256 _startTimestamp, uint256 _secondsPerPeriod,
    uint256 _totalPeriods, uint256 _cliffDuration,
    uint256 _tokens, address tokenAddress
  ) {
    require(_startTimestamp >= block.timestamp);
    require(_secondsPerPeriod > 0);
    require(_totalPeriods > 0);
    require(tokenAddress != address(0));
    require(_cliffDuration < _totalPeriods);
    require(_tokens > 0);

    startTimestamp = _startTimestamp;
    secondsPerPeriod = _secondsPerPeriod;
    totalPeriods = _totalPeriods;
    cliffDuration = _cliffDuration;
    tokens = _tokens;
    token = LifToken(tokenAddress);
  }