Can't OR any JournalOpenModes together

[panzi]

The SystemD documentation of sd_journal_open() says:

The second argument is a flags field, which may consist of the following flags ORed together:

See: https://www.freedesktop.org/software/systemd/man/latest/sd_journal_open.html

But the JournalOpenMode._missing_ disallows any ORed value:

cysystemd/cysystemd/reader.pyx

Lines 147 to 157 in 36424aa

	@classmethod
	def _missing_(cls, value) -> 'JournalOpenMode':
	if value == SD_JOURNAL_SYSTEM_ONLY:
	warnings.warn(
	"The JournalOpenMode.SYSTEM_ONLY is deprecated and the alias of "
	"JournalOpenMode.SYSTEM in the systemd library.",
	DeprecationWarning,
	stacklevel=2
	)
	return cls.SYSTEM
	raise ValueError(f"{value} is not a valid open mode")

SystemD defines SD_JOURNAL_SYSTEM_ONLY to be the same as SD_JOURNAL_SYSTEM anyway, rendering the _missing_() method useless for that case:

https://github.com/systemd/systemd/blob/49eb2d50b4328956b0d8fdf173425e2029b7d5ee/src/systemd/sd-journal.h#L74

Except it breaks ORing! I currently hack-fix this bug in my code with this line:

del JournalOpenMode._missing_

I suggest to just remove that method.