network: Avoid notifier re-creating in connect function

Author: xndcn

canopen/network.py

@@ -107,7 +107,8 @@ def connect(self, *args, **kwargs) -> Network:
         if self.bus is None:
             self.bus = can.Bus(*args, **kwargs)
         logger.info("Connected to '%s'", self.bus.channel_info)
-        self.notifier = can.Notifier(self.bus, self.listeners, self.NOTIFIER_CYCLE)
+        if self.notifier is None:
+            self.notifier = can.Notifier(self.bus, self.listeners, self.NOTIFIER_CYCLE)
         return self
 
     def disconnect(self) -> None:
@@ -123,7 +124,13 @@ def disconnect(self) -> None:
         if self.bus is not None:
             self.bus.shutdown()
         self.bus = None
-        self.check()
+        try:
+            self.check()
+        except Exception as e:
+            raise e
+        finally:
+            # Release notifier after check
+            self.notifier = None
 
     def __enter__(self):
         return self