Something that tripped me up when working on #746, is that FileSystemStoreBackend.__repr__ makes it look like a string. I could not find a good reason for this. Do you remember something about this @aabadie?

Here is a snippet to show what I mean:

In [1]: from joblib import Memory

In [2]: mem = Memory('/tmp/test')

In [3]: mem.store_backend
Out[3]: /tmp/test/joblib

When I was debugging I lost at least one hour until I thought of doing type(mem.store_backend) ...

Also slightly less important but:

from joblib._store_backends import FileSystemStoreBackend
backend = FileSystemStoreBackend()
backend  # Exception in __repr__ AttributeError: 'FileSystemStoreBackend' object has no attribute 'location'