Add detection for empty domain_objects

Author: bouwew

plugwise/helper.py

@@ -229,6 +229,9 @@ def _get_locations(self) -> None:
         """Collect all locations."""
         loc = Munch()
         locations = self._domain_objects.findall("./location")
+        if not locations:
+            raise KeyError("No data present!")
+
         for location in locations:
             loc.loc_id = location.attrib["id"]
             loc.name = location.find("name").text