Format Specifiers for binary representation of integers fails if using '_' separator

[someyob]

CircuitPython version

Adafruit CircuitPython 8.2.9 on 2023-12-06; Raspberry Pi Pico with rp2040

Code/REPL

>>> print(f'{63456:,}')
63,456
>>> print(f'{63456:b}')
1111011111100000
>>> print(f'{63456:_b}')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: invalid format specifier
>>>

Behavior

print(f'{63456:,}')
63,456
print(f'{63456:b}')
1111011111100000
print(f'{63456:_b}')
Traceback (most recent call last):
File "", line 1, in
ValueError: invalid format specifier

Description

The '_' separator for formatting an integer as a binary (string) was included in Python 3.4 (afaik), but it fails in CircuitPython.

Additional information

No response

[jepler]

I went ahead and marked this as an enhancement request, but I also implemented it and offered it to upstream at micropython#13516 -- I think this could be very useful and would like to see it added.

[someyob]

Thanks, Jeff. A small thing, but makes life simpler.
Cheers