I recommend to use os.path.sep, since it's the path separator, it will make it very clear. But here, consistency plays an important role. In case, if you are started using one, use that. Otherwise, just pick other one and use it all the time
>>> os.path.join("foo", "bar", "baz")
'foo/bar/baz'
>>> os.path.split(_)
('foo/bar', 'baz')
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