Improve binary insertion sort comparable typing

sorts/adaptive_merge_sort.py

@@ -49,7 +49,7 @@ def merge(array: list, aux: list, low: int, mid: int, high: int) -> None:
     for k in range(low, high + 1):
         array[k] = aux[k]
 
-    print(f"After merge: {array[low:high + 1]}")
+    print(f"After merge: {array[low : high + 1]}")
 
 
 # Example usage

sorts/binary_insertion_sort.py

@@ -10,8 +10,17 @@
 python binary_insertion_sort.py
 """
 
+from typing import Protocol, TypeVar
 
-def binary_insertion_sort(collection: list) -> list:
+
+class Comparable(Protocol):
+    def __lt__(self, other: object, /) -> bool: ...
+
+
+T = TypeVar("T", bound=Comparable)
+
+
+def binary_insertion_sort[T: Comparable](collection: list[T]) -> list[T]:
     """
     Sorts a list using the binary insertion sort algorithm.
 
@@ -36,6 +45,10 @@ def binary_insertion_sort(collection: list) -> list:
     >>> collection = random.choices(string.ascii_letters + string.digits, k=100)
     >>> binary_insertion_sort(collection) == sorted(collection)
     True
+    >>> binary_insertion_sort([1, "a"])
+    Traceback (most recent call last):
+    ...
+    TypeError: '<' not supported between instances of 'str' and 'int'
     """
 
     n = len(collection)

tests/test_sorts.py

@@ -87,3 +87,8 @@ def test_heap_sort():
 def test_sort_matches_builtin(sort, case):
     """Each sort must reproduce the ordering of the built-in ``sorted``."""
     assert list(sort(list(case))) == sorted(case)
+
+
+def test_binary_insertion_sort_rejects_non_comparable_items():
+    with pytest.raises(TypeError):
+        binary_insertion_sort([1, "a"])