下文是关于不可争辩条款的原文，请帮助翻译，尤其是后半部分，难译。

The policy shall provide that the validity of the policy shall not be contested, except for nonpayment of premiums, after it has been in force for two years from its date ofissue; and that no statement made by any employee insured under the policy relatingto his or her insurability shall be used in contesting the validity of theinsurance with respect to which the statement was made after the insurancehas been in force prior to the contest for a period of two years during the employee's lifetime nor unless it is contained in a written application signedby the employee.