contract Whitelistable {
    Whitelist public whitelist;

    modifier whenWhitelisted(address _wallet) {
        require(whitelist.isWhitelisted(_wallet));
        _;
    }

    /**
    * @dev Constructor for Whitelistable contract.
    */
    function Whitelistable() public {
        whitelist = new Whitelist();
    }
}
function Whitelistable() public {
    whitelist = new Whitelist();
}

/**
 * @dev Constructor for Whitelistable contract.
 */