Implement .get() as suggested

Author: bouwew

plugwise/legacy/helper.py

@@ -258,7 +258,7 @@ def _get_measurement_data(self, entity_id: str, entity: GwEntityData) -> None:
         # Get P1 smartmeter data from MODULES
         # !! DON'T CHANGE below two if-lines, will break stuff !!
         if self.smile.type == "power":
-            if entity["dev_class"] == "smartmeter":
+            if entity.get("dev_class") == "smartmeter":
                 data.update(self._power_data_from_modules())
 
             entity.update(data)