If the validity period of the contract is stipulated in the contract, the contract will naturally become invalid after the validity period. The invalidity of the contract is only the invalidity of the agreed terms in the contract, and does not affect the continued performance of the effective part of the contract itself, that is, after the expiration of the contract, some subsequent matters after the expiration of the contract should be handled according to the General Principles of the Civil Law and the Public Order and Good Customs, and should continue to be done well. One party shall not take advantage of the expiration of the contract to encroach on the legitimate rights and interests of the other party, that is, matters not agreed in the contract shall be handled through consultation according to public order and good customs.