Merge pull request #225 from andlaus/no_dataclass_internals

`dataclass_fields_asdict()`: do not use internals of the dataclass implementation

odxtools/utils.py

@@ -1,4 +1,5 @@
 # SPDX-License-Identifier: MIT
+import dataclasses
 import re
 from typing import Any, Dict, Optional
 from xml.etree import ElementTree
@@ -31,10 +32,12 @@ def create_description_from_et(et_element: Optional[ElementTree.Element],) -> Op
 def dataclass_fields_asdict(obj: Any) -> Dict[str, Any]:
     """Extract all attributes from a dataclass object that are fields.
 
-    This makes hierarchies of dataclasses possible while initializing
-    the base class using common code.
+    This is a non-recursive version of `dataclasses.asdict()`. Its
+    purpose is to make hierarchies of dataclasses possible while
+    initializing the base class using common code.
+
     """
-    return {x.name: getattr(obj, x.name) for x in obj.__dataclass_fields__.values()}
+    return {x.name: getattr(obj, x.name) for x in dataclasses.fields(obj)}
 
 
 # ISO 22901 section 7.1.1