bytes.fromhex ignores space characters now (yay!) but still barfs if fed newlines or tabs:

>>> bytes.fromhex('ab\ncd')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: non-hexadecimal number found in fromhex() arg at position 2
>>> bytes.fromhex('ab\tcd')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: non-hexadecimal number found in fromhex() arg at position 2

It's often quite useful to paste blobs of hex into source code (or the REPL) and call ".fromhex" on them. These might include spaces, tabs and/or newlines, and barfing on these other whitespace characters is inconvenient.

I propose that bytes.fromhex should ignore all whitespace. A patch + test is attached.