... object has no attribute '_dbus'

from sdbus import (DbusInterfaceCommonAsync, dbus_method_async,
                   request_default_bus_name_async)
from asyncio import new_event_loop

class HelloInterface(
    DbusInterfaceCommonAsync,
    interface_name='org.example.interface'
):
    def __init__(self, hello):
        self.hello = hello

    @dbus_method_async(
        input_signature='s',
        result_signature='s',
    )
    async def hello(self, string: str) -> str:
        return self.hello.say_hello_back(str)

class Hello:
    def say_hello_back(str):
        return "Hello {str}!"

hello = Hello()
i = HelloInterface(hello)

async def startup() -> None:
    await request_default_bus_name_async('org.example.test')
    i.export_to_dbus('/')

loop = new_event_loop()

loop.run_until_complete(startup())
loop.run_forever()

Traceback (most recent call last):
  File "/tmp/test/hello_interface.py", line 32, in <module>
    loop.run_until_complete(startup())
    ~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^
  File "/usr/lib/python3.13/asyncio/base_events.py", line 725, in run_until_complete
    return future.result()
           ~~~~~~~~~~~~~^^
  File "/tmp/test/hello_interface.py", line 28, in startup
    i.export_to_dbus('/')
    ~~~~~~~~~~~~~~~~^^^^^
  File "/usr/lib/python3/dist-packages/sdbus/dbus_proxy_async_interface_base.py", line 322, in export_to_dbus
    local_object_meta = self._dbus
                        ^^^^^^^^^^
AttributeError: 'HelloInterface' object has no attribute '_dbus'