有效期以甲乙双方中最后一方签字或盖章的日期为准的翻译：Validity period with reference to both parties last party in whichever signature or seal 什么意思？中文翻译英文，英文翻译中文，怎么说？

青云英语翻译

Valid for both parties sign or seal the last one shall be the date

Validity period with reference to both parties last party in whichever signature or seal

The term of validity last the side signs the date take armor second grade both sides in which or stamps as

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Validity period with reference to both parties last party in whichever signature or seal