Said so many times rewriting,This time we have to rewrite treat seriously what method。
contract
We say,Inheritance is the equivalent of signing a contract,We inherited out of the subclass must comply with this contract,So even if you want to do something where no contract,Must comply with contract specifications,so,You override methods,It must also comply with the type of process。
We talked about the type of approach,It ()->() Such[……]