contract Timestamped {
    /**
    * @dev Returns current timestamp.
    */
    function _currentTime() internal view returns(uint256) {
        // solium-disable-next-line security/no-block-members
        return block.timestamp;
    }
}
/**
 * @title Timestamped
 * @dev Timestamped contract has a separate method for receiving current timestamp.
 * This simplifies derived contracts testability.
 */
function _currentTime() internal view returns(uint256) {
    // solium-disable-next-line security/no-block-members
    return block.timestamp;
}

/**
 * @dev Returns current timestamp.
 */