quick fix

Author: patrickvonplaten

src/diffusers/utils/import_utils.py

@@ -571,7 +571,7 @@ class DummyObject(type):
     """
 
     def __getattr__(cls, key):
-        if key.startswith("_"):
+        if key.startswith("_") and key != "_load_connected_pipes":
             return super().__getattr__(cls, key)
         requires_backends(cls, cls._backends)