fcache | performance HTTP cache , based on file , suitable for CDN | HTTP library

In my PyQt5 app, I've been using fache (https://pypi.org/project/fcache/) to cache lots of small files to the user's temp folder for speed. It's working well for caching, but now I need to be able to iterate through the cached files and selectively delete files that are no longer needed.

However when I try to iterate through the FileCache object, I'm getting an error.

thisCache is the name of my cache, and if I print(thisCache) I get: which is fine.

Then if I do print(thisCache.keys()) I get KeysView(), which seems correct (I think?). Similarly, printing .values() gives me a ValuesView.

Then if I do print(len(thisCache.keys()) I get: 1903, showing that there are 1903 files in there, which is probably correct. But here's where I get stuck.

If I try to iterate through the KeysView in any way, I get an error. Each of the following attempts: for f in thisCache.values(): for f in thisCache.keys(): always throws an error: Process finished with exit code -1073740791 (0xC0000409)

I'm fairly new to Python, so am I just misunderstanding how I'm supposed to iterate through this list? Or is there a bug or gotcha here that I need to work around?

Thanks

::::::::: EDIT ::::::::

After a bit of a delay, here's a reproducile (but not especially minimal or quality) bit of example code.