Ethan,

a recent change to enum module breaks ssltests. I'm running ssltests with python -Werror to detect deprecation issues. Could you please look into the matter and address the deprecation warning in asyncio?

https://github.com/python/cpython/runs/2477299020

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ERROR: test_add_signal_handler_install_error3 (test.test_asyncio.test_unix_events.SelectorEventLoopSignalTests)
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test test_asyncio failed
Traceback (most recent call last):
  File "/home/runner/work/cpython/cpython/Lib/asyncio/unix_events.py", line 116, in add_signal_handler
    signal.signal(sig, _sighandler_noop)
  File "/home/runner/work/cpython/cpython/Lib/unittest/mock.py", line 1105, in __call__
    return self._mock_call(*args, **kwargs)
  File "/home/runner/work/cpython/cpython/Lib/unittest/mock.py", line 1109, in _mock_call
    return self._execute_mock_call(*args, **kwargs)
  File "/home/runner/work/cpython/cpython/Lib/unittest/mock.py", line 1164, in _execute_mock_call
    raise effect
test.test_asyncio.test_unix_events.SelectorEventLoopSignalTests.test_add_signal_handler_install_error3.<locals>.Err

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/runner/work/cpython/cpython/Lib/unittest/mock.py", line 1370, in patched
    return func(*newargs, **newkeywargs)
  File "/home/runner/work/cpython/cpython/Lib/test/test_asyncio/test_unix_events.py", line 165, in test_add_signal_handler_install_error3
    self.assertRaises(
  File "/home/runner/work/cpython/cpython/Lib/unittest/case.py", line 732, in assertRaises
    return context.handle('assertRaises', args, kwargs)
  File "/home/runner/work/cpython/cpython/Lib/unittest/case.py", line 201, in handle
    callable_obj(*args, **kwargs)
  File "/home/runner/work/cpython/cpython/Lib/asyncio/unix_events.py", line 129, in add_signal_handler
    raise RuntimeError(f'sig {sig} cannot be caught')
  File "/home/runner/work/cpython/cpython/Lib/enum.py", line 1019, in __format__
    warnings.warn(
DeprecationWarning: in 3.12 format() will use the enum member, not the enum member's value;
use a format specifier, such as :d for an IntEnum member, to maintainthe current display