async def async_added_to_hass(self) -> None:
        """Register callbacks and load initial data."""

        for event in self._hm_channel_events:
            self._unregister_callbacks.append(
                event.register_data_point_updated_callback(cb=self._async_event_changed, custom_id=self.entity_id)
            )
            self._unregister_callbacks.append(event.register_device_removed_callback(cb=self._async_device_removed))
Register callbacks and load initial data.
custom_components/homematicip_local/event.py