The term "bytes-like object" is specifically designed for those situations where python used to say "X does not support the buffer interface" if passed something else.  Which is the case here...now it says "a bytes-like object is required".  I'm not sure if we fixed that everywhere, but I think we did.  It is certainly true in the cases you cite, except that it turns out that ignorechars accepts an ASCII string.

So, if there is any sort of remaining problem, it is a separate issue: my edits match the current error message behavior.  I'll fix ignorechars and commit.