Core Data: Fetched attributes with joined tables

I have a Host which has a many-to-many relationship with services. The relation is through a join table "hostServices". I would like to fetch te services related to a Host via a "fetched property". But how do I define the predicate?

I now did something like 'ANY hostServices.host.name == 开发者_C百科"$FETCH_SOURCE.name"' and I have tried 'ANY hostServices.host == "$FETCH_SOURCE"'.

But that didn't work. Does anyone know how I could fetch the services?

Thanks in advance!

My data model

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Try:

host == $FETCH_SOURCE