If they are not required by the Membership provider, no exception is thrown if they are not found, and if they are of the wrong type they are ignored.

如果成员资格提供程序不需要它们，即使找不到它们也不会引发异常，如果它们的类型错误，则它们将被忽略。

youdao

No membership is required.

BBC: The Dutch beach library

Once state employees were no longer required to maintain union membership to keep their jobs, they left public sector unions in droves.

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