func: function vestedAmount(ERC20Basic token) public view returns (uint256) {
          uint256 currentBalance = token.balanceOf(this);
          uint256 totalBalance = currentBalance.add(released[token]);
  
          if (block.timestamp < cliff) {
              return 0;
          } else if (block.timestamp >= start.add(duration) || revoked[token]) {
              return totalBalance;
          } else {
              return totalBalance.mul(block.timestamp.sub(start)).div(duration);
          }
      }