Fix non-thermostats

Author: bouwew

plugwise/__init__.py

@@ -86,9 +86,11 @@ def __init__(
         self.smile_zigbee_mac_address: str | None = None
 
     @property
-    def cooling_present(self) -> str:
+    def cooling_present(self) -> str | None:
         """Return the cooling capability."""
-        return self._smile_props["cooling_present"]
+        if "cooling_present" in self._smile_props:
+            return self._smile_props["cooling_present"]
+        return None
 
     @property
     def gateway_id(self) -> str: