Clone the queryset before iterating over it
Clone the queryset before iterating over it

test_clear_prefetch_related calls `list(qss)` twice.  The first call
changes `qss.query.high_mark` from `None` to 3 (2 books, 3 articles),
see
https://github.com/percipient/django-querysetsequence/blob/3b55942a4c4038ba7e997cef937760d5c92e0b0b/queryset_sequence/__init__.py#L214-L216

The secend call now limits the queryset sequence to 3 elements, and
sets `high_mark` to 1.

percipient/django-querysetsequence