Fix nordpool Not to return Unknown if price is exactly 0

homeassistant/components/nordpool/sensor.py

@@ -34,9 +34,12 @@ def validate_prices(
     index: int,
 ) -> float | None:
     """Validate and return."""
-    if result := func(entity)[area][index]:
-        return result / 1000
-    return None
+    result = func(entity)[area][index]
+    if result is None:
+        return None
+    if result == 0:
+        return 0
+    return result / 1000
 
 
 def get_prices(
@@ -401,4 +404,7 @@ def __init__(
     def native_value(self) -> float | None:
         """Return value of sensor."""
         data = self.coordinator.get_data_current_day()
-        return data.area_average[self.area] / 1000
+        value = data.area_average.get(self.area)
+        if value is None:
+            return None
+        return value / 1000