Apply suggestions from code review

Signed-off-by: Thijs Baaijen <13253091+Thijss@users.noreply.github.com>

Author: Thijss

src/power_grid_model_ds/_core/model/arrays/base/array.py

@@ -19,7 +19,11 @@
 from power_grid_model_ds._core.model.arrays.base._string import convert_array_to_string
 from power_grid_model_ds._core.model.arrays.base.errors import ArrayDefinitionError
 from power_grid_model_ds._core.model.constants import EMPTY_ID, empty
-from power_grid_model_ds._core.utils.misc import array_equal_with_nan, build_mro_attribute, get_public_annotations
+from power_grid_model_ds._core.utils.misc import (
+    array_equal_with_nan,
+    combine_attribute_from_parent_classes,
+    get_public_annotations,
+)
 
 # pylint: disable=missing-function-docstring, too-many-public-methods
 
@@ -80,13 +84,13 @@ def data(self) -> NDArray:
     @classmethod
     @lru_cache
     def get_defaults(cls) -> dict[str, Any]:
-        return build_mro_attribute(cls, "_defaults", attribute_type=dict)
+        return combine_attribute_from_parent_classes(cls, "_defaults", attribute_type=dict)
 
     @classmethod
     @lru_cache
     def get_dtype(cls):
         annotations = get_public_annotations(cls)
-        str_lengths = build_mro_attribute(cls, "_str_lengths", dict)
+        str_lengths = combine_attribute_from_parent_classes(cls, "_str_lengths", dict)
         dtypes = {}
         for name, dtype in annotations.items():
             if len(dtype.__args__) > 1:

src/power_grid_model_ds/_core/utils/misc.py

@@ -5,7 +5,7 @@
 """Misc utils"""
 
 from collections.abc import Sequence
-from typing import get_type_hints, overload
+from typing import get_type_hints
 
 import numpy as np
 
@@ -30,34 +30,27 @@ def get_public_annotations(cls: type):
     return {attr: type_ for attr, type_ in class_attributes.items() if not attr.startswith("_")}
 
 
-@overload
-def build_mro_attribute(cls: type, attribute_name: str, attribute_type: type[dict]) -> dict: ...
-
-
-@overload
-def build_mro_attribute(cls: type, attribute_name: str, attribute_type: type[set]) -> set: ...
-
-
-def build_mro_attribute(cls: type, attribute_name: str, attribute_type) -> dict | set:
+def combine_attribute_from_parent_classes[T: (dict, set)](cls: type, attribute_name: str, attribute_type: type[T]) -> T:
     """Combine all versions of an attribute in the Method Resolution Order (mro) of a class into a single attribute
 
     For dicts this means the dict is updated so that child classes override parent classes.
     For sets this means the sets are unioned together.
 
     Types other than dict and set are not supported
     """
-    attr_value = attribute_type()
+    combined_attr = attribute_type()
     for parent in reversed(list(cls.__mro__)):
+        parent_attr = getattr(parent, attribute_name, attribute_type())
         if attribute_type is dict:
-            attr_value.update(getattr(parent, attribute_name, {}))
+            combined_attr.update(parent_attr)
         elif attribute_type is set:
-            attr_value |= getattr(parent, attribute_name, set())
+            combined_attr |= parent_attr
         else:
             raise NotImplementedError(
                 f"Type {attribute_type} cannot combine inherited for attribute {attribute_name}. "
                 f"Only dict and set are currently supported."
             )
-    return attr_value
+    return combined_attr
 
 
 def array_equal_with_nan(array1: np.ndarray, array2: np.ndarray) -> bool:

tests/unit/utils/test_misc.py

@@ -8,7 +8,7 @@
 
 from power_grid_model_ds._core.utils.misc import (
     array_equal_with_nan,
-    build_mro_attribute,
+    combine_attribute_from_parent_classes,
     get_public_annotations,
     is_sequence,
 )
@@ -67,16 +67,16 @@ def test_get_public_class_attrs():
 
 
 def test_build_mro_attribute_set():
-    attr = build_mro_attribute(_ChildClass, attribute_name="a", attribute_type=set)
+    attr = combine_attribute_from_parent_classes(_ChildClass, attribute_name="a", attribute_type=set)
     assert attr == {1, 2, 3, 4, 5}
 
 
 def test_build_mro_attribute_dict():
     assert _ChildClass.b == {2: "b", 3: "ccc"}
-    attr = build_mro_attribute(_ChildClass, attribute_name="b", attribute_type=dict)
+    attr = combine_attribute_from_parent_classes(_ChildClass, attribute_name="b", attribute_type=dict)
     assert attr == {1: "a", 2: "b", 3: "ccc"}
 
 
 def test_build_mro_attribute_list():
     with pytest.raises(NotImplementedError):
-        build_mro_attribute(_ChildClass, attribute_name="c", attribute_type=list)
+        combine_attribute_from_parent_classes(_ChildClass, attribute_name="c", attribute_type=list)