fix(testing): pytest.approx returns a clearer error mesage when comparing mappings with different keys

Author: cmnemoi

testing/python/approx.py

@@ -1,21 +1,18 @@
 # mypy: allow-untyped-defs
 from __future__ import annotations
 
-from contextlib import contextmanager
 import decimal
-from decimal import Decimal
-from fractions import Fraction
-from math import inf
-from math import nan
-from math import sqrt
 import operator
-from operator import eq
-from operator import ne
 import re
+from contextlib import contextmanager
+from decimal import Decimal
+from fractions import Fraction
+from math import inf, nan, sqrt
+from operator import eq, ne
 
+import pytest
 from _pytest.pytester import Pytester
 from _pytest.python_api import _recursive_sequence_map
-import pytest
 from pytest import approx