Use ENERGY device class in oru (#84225)

* Use ENERGY device class in oru

* Apply suggestions from code review

Co-authored-by: Franck Nijhof <frenck@frenck.nl>

Co-authored-by: Franck Nijhof <frenck@frenck.nl>

homeassistant/components/oru/sensor.py

@@ -7,8 +7,12 @@ import logging
 from oru import Meter, MeterError
 import voluptuous as vol
 
-from homeassistant.components.sensor import PLATFORM_SCHEMA, SensorEntity
-from homeassistant.const import ENERGY_KILO_WATT_HOUR
+from homeassistant.components.sensor import (
+    PLATFORM_SCHEMA,
+    SensorDeviceClass,
+    SensorEntity,
+)
+from homeassistant.const import UnitOfEnergy
 from homeassistant.core import HomeAssistant
 import homeassistant.helpers.config_validation as cv
 from homeassistant.helpers.entity_platform import AddEntitiesCallback
@@ -20,9 +24,6 @@ CONF_METER_NUMBER = "meter_number"
 
 SCAN_INTERVAL = timedelta(minutes=15)
 
-SENSOR_NAME = "ORU Current Energy Usage"
-SENSOR_ICON = "mdi:counter"
-
 PLATFORM_SCHEMA = PLATFORM_SCHEMA.extend({vol.Required(CONF_METER_NUMBER): cv.string})
 
 
@@ -51,12 +52,12 @@ def setup_platform(
 class CurrentEnergyUsageSensor(SensorEntity):
     """Representation of the sensor."""
 
-    _attr_icon = SENSOR_ICON
-    _attr_native_unit_of_measurement = ENERGY_KILO_WATT_HOUR
+    _attr_device_class = SensorDeviceClass.ENERGY
+    _attr_name = "ORU Current Energy Usage"
+    _attr_native_unit_of_measurement = UnitOfEnergy.KILO_WATT_HOUR
 
     def __init__(self, meter):
         """Initialize the sensor."""
-        self._state = None
         self._available = None
         self.meter = meter
 
@@ -65,26 +66,19 @@ class CurrentEnergyUsageSensor(SensorEntity):
         """Return a unique, Home Assistant friendly identifier for this entity."""
         return self.meter.meter_id
 
-    @property
-    def name(self):
-        """Return the name of the sensor."""
-        return SENSOR_NAME
-
-    @property
-    def native_value(self):
-        """Return the state of the sensor."""
-        return self._state
-
     def update(self) -> None:
         """Fetch new state data for the sensor."""
         try:
             last_read = self.meter.last_read()
 
-            self._state = last_read
+            self._attr_native_value = last_read
             self._available = True
 
             _LOGGER.debug(
-                "%s = %s %s", self.name, self._state, self.unit_of_measurement
+                "%s = %s %s",
+                self.name,
+                self.native_value,
+                self.native_unit_of_measurement,
             )
         except MeterError as err:
             self._available = False