    def unique_id(self):
        """
        "Uniquely identify this sensor so that it gets stored in the entity_registry,
        and can be maintained / renamed etc by the user.
        """
        return f"{self._device.unique_id}_ref_power"
"Uniquely identify this sensor so that it gets stored in the entity_registry,
and can be maintained / renamed etc by the user.
custom_components/bermuda/number.py