contract Faucet {

    // Give out ether to anyone who asks
    function withdraw(uint withdraw_amount) public {

        // Limit withdrawal amount  1 eth = 1 * 10的18次方 
        require(withdraw_amount <= 100000000000000000);

        // Send the amount to the address that requested it
        payable(msg.sender).transfer(withdraw_amount);
    }

    // Accept any incoming amount
    fallback () external payable {}

}