Correct logic in message delivery and directory management (apache#42)

* Logical Error Fixed in delivererers.py inside src and cluster/directories.py

* The Deliverers Module is deprecated and not used by any other module; furthermore, the documentation does not mention this module

Author: Advaitgaur004

src/dubbo/cluster/directories.py

@@ -46,7 +46,7 @@ def notify(self, urls: list[URL]) -> None:
         # create new invokers
         for url in urls:
             k = str(url)
-            if k in old_invokers.items():
+            if k in old_invokers:
                 self._invokers[k] = old_invokers[k]
                 del old_invokers[k]
             else: