问错误：- browser/Mycontract.sol:29:13:错误:未声明的标识符。断言(值% 10 == 0)；^-^

EN

pragma solidity ^0.4.7 ;

contract MyContract
{
    string sentence = "my first sentence" ;
    address owner ;
    function MyContract()
    {
        owner = msg.sender ;

    }
    function getSentence() public constant returns(string)     {
        return sentence ;
    }
        function setSentence(string newsentence) public returns (string)
        {
            if(owner!= msg.sender)
            {
                return "don't dare to change the contract" ;
            }
            sentence = newsentence ;
            return sentence ;

        }
        uint balance=100 ;
        uint value ;
        function Transact(uint value) public returns(uint)
        {
            assert(value % 10 == 0) ;
            require(value<= balance) ;
            balance = balance - value ;
            return balance ;
        }

}