Consistently use byte/str everywhere about solaar

[pwr]

Hm, read() and write() in hidapi/udev.py should always use bytes; I've added some asserts there and haven't triggered them yet. Have you gotten anything else in your tests?

[Lekensteyn]

I haven't triggered any assertions yet on these functions, but I do not know for sure if every code path is safe, hence this issue.

What I have experienced is that sometimes concatenating a string fails when a byte (str) contains an invalid Unicode sequence (Python 2). (bytes and str cannot be concatenated in Python3 without explicit conversion). (I fixed this when encountering this).

[Lekensteyn]

Oh, you actually meant that you have added assertions at the time of posting. Well, that assertion is always true on Python2 (not on Python3 though):

$ python2 -c 'print isinstance("", bytes)'
True
$ python3 -c 'print(isinstance("", bytes))'
False

[Lekensteyn]

Probably fixed by now.