CR: verify _start_node_discover is properly set before calling

Author: dirixmjm

plugwise_usb/network/registry.py

@@ -197,7 +197,13 @@ async def update_missing_registrations_circleplus(self) -> None:
                     continue
                 _maintenance_registry.append(mac)
                 if self.update_network_registration(mac):
-                    await self._start_node_discover(mac, None, False)
+                    if self._start_node_discover is not None:
+                        await self._start_node_discover(mac, None, False)
+                    else:
+                        _LOGGER.debug(
+                            "No start_node_discover callback set; skipping for %s", mac
+                        )
+
             await sleep(self._registration_scan_delay)
         _LOGGER.debug("CirclePlus registry scan finished")
         self._scan_completed = True
@@ -218,7 +224,12 @@ async def load_registrations_from_cache(self) -> None:
             )
         for mac, nodetype in self._network_cache.nodetypes.items():
             self.update_network_registration(mac)
-            await self._start_node_discover(mac, nodetype, True)
+            if self._start_node_discover is not None:
+                await self._start_node_discover(mac, nodetype, True)
+            else:
+                _LOGGER.debug(
+                    "No start_node_discover callback set; skipping for %s", mac
+                )
             await sleep(0.1)
         _LOGGER.info("Cache network registration discovery finished")
         if self._scan_completed_callback is not None:
@@ -245,7 +256,12 @@ async def register_node(self, mac: str) -> None:
         except StickError as exc:
             raise NodeError(f"{exc}") from exc
         if self.update_network_registration(mac):
-            await self._start_node_discover(mac, None, False)
+            if self._start_node_discover is not None:
+                await self._start_node_discover(mac, None, False)
+            else:
+                _LOGGER.debug(
+                    "No start_node_discover callback set; skipping for %s", mac
+                )
 
     async def unregister_node(self, mac: str) -> None:
         """Unregister node from current Plugwise network."""