Rework _ZeroconfListener to correct typing

_zeroconf.get_service_info might return None on timeout, and services
without any service info are no good to us, so reject those and ensure
that we only have the right types in our dict.

Also, inherit from ServiceListener, to show that we're of the right type.

homeassistant_cli/config.py

@@ -15,21 +15,24 @@
 _LOGGING = logging.getLogger(__name__)
 
 
-class _ZeroconfListener:
+class _ZeroconfListener(zeroconf.ServiceListener):
     def __init__(self) -> None:
         self.services = {}  # type: Dict[str, zeroconf.ServiceInfo]
 
     def remove_service(
         self, _zeroconf: zeroconf.Zeroconf, _type: str, name: str
     ) -> None:
         """Remove service."""
-        self.services[name] = None
+        del self.services[name]
 
     def add_service(
         self, _zeroconf: zeroconf.Zeroconf, _type: str, name: str
     ) -> None:
         """Add service."""
-        self.services[name] = _zeroconf.get_service_info(_type, name)
+        service = _zeroconf.get_service_info(_type, name)
+        # Reject services which time out
+        if service:
+            self.services[name] = service
 
 
 def _locate_ha() -> Optional[str]: