@arooni: That looks like a genuine bug, will look into it

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@rolgiati: AFAICT, that's from the vanilla Collections handling in the Kindle driver, not this plugin (and that's basically useless and/or very very limited), and it's basically unmaintained, so I can't really tell you much about it.
If that's actually somehow triggered by the plugin, I'm going to have to know what exactly you were attempting to do, because I can't see it from that stacktrace

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