'DeviceAllow' option missing from KNOWN_UNIT_SIGNATURES

[barometz]

While testing a service with restricted access to /dev I ran into the following error:

  File "/opt/share/uv/<...>/lib/python3.12/site-packages/<...>/runner.py", line 135, in run
    unit: Unit = pystemd.run(
                 ^^^^^^^^^^^^
  File "/opt/share/uv/<...>/lib/python3.12/site-packages/pystemd/run.py", line 306, in run
    unit_start_job = manager.Manager.StartTransientUnit(
                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/share/uv/<...>/lib/python3.12/site-packages/pystemd/base.py", line 219, in _call
    return func(self, name, *args)
           ^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/share/uv/<...>/lib/python3.12/site-packages/pystemd/base.py", line 178, in _call_method
    return overwrite_method(self.interface_name, *args)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/share/uv/<...>/lib/python3.12/site-packages/pystemd/systemd1/manager.py", line 44, in StartTransientUnit
    args += signature_array(properties)
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/share/uv/<...>/lib/python3.12/site-packages/pystemd/systemd1/unit_signatures.py", line 384, in signature_array
    signature = KNOWN_UNIT_SIGNATURES[prop_name]
                ~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^
KeyError: b'DeviceAllow'

Sure enough, DeviceAllow is not defined in unit_signatures.py, while the related DevicePolicy is. DeviceAllow is present in the dbus interface at https://github.com/systemd/systemd/blob/v237/src/core/dbus-cgroup.c#L325. Was this just missed while copying options, or is it left out on purpose?

(as an aside, thanks for pystemd, I'm thrilled that I didn't have to figure out how dbus actually works to talk to systemd).