warnings.warn is weird

[00001H]

warnings.warn shows the message above the traceback, and NoneType is here for some reason (the default category should be UserWarning, even though the default argument is indeed None)

Brython 3.13.0 on Netscape 5.0 (Windows)
Type "help", "copyright", "credits" or "license" for more information.
>>> import warnings
>>> warnings.warn("hello")
<stdin>:1: NoneType: hello
  warnings.warn("hello")
>>> 

compare this with CPython:

Python 3.12.5 (tags/v3.12.5:ff3bc82, Aug  6 2024, 20:45:27) [MSC v.1940 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license()" for more information.
>>> import warnings
>>> warnings.warn("hello")
Warning (from warnings module):
  File "<pyshell#1>", line 1
UserWarning: hello
>>>