Update canopen/objectdictionary/__init__.py

From review, direct access to the template, we know this attribute exists.

Co-authored-by: André Colomb <github.com@andre.colomb.de>

Author: bizfsc

canopen/objectdictionary/__init__.py

@@ -298,7 +298,7 @@ def __getitem__(self, subindex: Union[int, str]) -> ODVariable:
                          "bit_definitions", "storage_location"):
                 if attr in template.__dict__:
                     var.__dict__[attr] = template.__dict__[attr]
-            var.custom_options = getattr(template, "custom_options", {})
+            var.custom_options = template.custom_options
         else:
             raise KeyError(f"Could not find subindex {pretty_index(None, subindex)}")
         return var