Until Python 3.8 hmc.new() defaulted the digestmod argument to 'hmac-md5'. This was deperecated, to be removed in Python 3.8. In Python 3.8.0b1 it is gone, e.g.

Python 3.8.0b1 (default, Jun  6 2019, 03:44:52) 
[GCC 7.4.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import hmac
>>> hmac.new(b'qwertyuiop').name
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python3.8/hmac.py", line 146, in new
    return HMAC(key, msg, digestmod)
  File "/usr/lib/python3.8/hmac.py", line 49, in __init__
    raise ValueError('`digestmod` is required.')
ValueError: `digestmod` is required.

but the deprecation note, and the documented signature haven't been updated.

PR incoming