How to connect to a BLE device that requires pairing with passkey?

Development
1

I am building an integration for a BLE device that requires pairing with a passkey - i followed the recommendations and i am using bleak, but it does not seem to show the passkey, neither on the device, nor am i able to retrieve it somehow from the device. How can i achieve this, so that i can add a step to my config_flow to accept the passkey?

        _LOGGER.debug("Connecting now:...")
        self._client = await establish_connection(
            BleakClient,
            device=self._ble_device,
            name=self._mac,
            disconnected_callback=self.diconnected_cb,
            max_attempts=3,
        )

        _LOGGER.debug(f"Connected: {self._client.is_connected}, now pairing.")

        success = await self._client.pair()
        _LOGGER.info(success)