diff --git a/custom_components/hpprinter/binary_sensor.py b/custom_components/hpprinter/binary_sensor.py
index 845ec5c..8eaab49 100644
--- a/custom_components/hpprinter/binary_sensor.py
+++ b/custom_components/hpprinter/binary_sensor.py
@@ -3,6 +3,8 @@
 For more details about this platform, please refer to the documentation at
 https://home-assistant.io/components/binary_sensor.hp_printer/
 """
+from __future__ import annotations
+
 import logging
 
 from homeassistant.components.binary_sensor import BinarySensorEntity
@@ -47,7 +49,7 @@ def is_on(self):
         return bool(self.entity.state)
 
     @property
-    def device_class(self) -> BinarySensorDeviceClass:
+    def device_class(self) -> BinarySensorDeviceClass | str | None:
         """Return the class of this sensor."""
         return self.entity.binary_sensor_device_class
 
diff --git a/custom_components/hpprinter/models/entity_data.py b/custom_components/hpprinter/models/entity_data.py
index 7dd56bb..db2b398 100644
--- a/custom_components/hpprinter/models/entity_data.py
+++ b/custom_components/hpprinter/models/entity_data.py
@@ -24,8 +24,8 @@ def __init__(self):
         self.device_name = ""
         self.status = ENTITY_STATUS_CREATED
         self.disabled = False
-        self.binary_sensor_device_class: None
-        self.sensor_device_class: None
+        self.binary_sensor_device_class = None
+        self.sensor_device_class = None
 
     def __repr__(self):
         obj = {
diff --git a/custom_components/hpprinter/sensor.py b/custom_components/hpprinter/sensor.py
index 493046b..487e593 100644
--- a/custom_components/hpprinter/sensor.py
+++ b/custom_components/hpprinter/sensor.py
@@ -3,8 +3,11 @@
 For more details about this platform, please refer to the documentation at
 https://home-assistant.io/components/binary_sensor.hp_printer/
 """
+from __future__ import annotations
+
 import logging
 
+from homeassistant.components.sensor import SensorEntity
 from homeassistant.core import HomeAssistant
 
 from .helpers.const import *
@@ -36,7 +39,7 @@ async def async_unload_entry(hass, config_entry):
     return True
 
 
-class HPPrinterSensor(HPPrinterEntity):
+class HPPrinterSensor(SensorEntity, HPPrinterEntity):
     """Representation a binary sensor that is updated by HP Printer."""
 
     @property
@@ -45,7 +48,7 @@ def native_value(self):
         return self.entity.state
 
     @property
-    def device_class(self) -> SensorDeviceClass:
+    def device_class(self) -> SensorDeviceClass | str | None:
         """Return the class of this sensor."""
         return self.entity.sensor_device_class