Update src/charm.py

Co-authored-by: Mehdi Bendriss <[email protected]>

src/charm.py

@@ -415,7 +415,7 @@ def _unit_ip(self) -> str:
         return str(self.model.get_binding(Config.Relations.PEERS).network.bind_address)
 
     @property
-    def is_external_client(self) -> Optional[str]:
+    def is_external_client(self) -> bool:
         """Returns the connectivity mode which mongos should use.
 
         Note that for K8s routers this should always default to True. However we still include