sorts: type cocktail shaker sort for comparable items

sorts/cocktail_shaker_sort.py

@@ -4,8 +4,14 @@
 https://en.wikipedia.org/wiki/Cocktail_shaker_sort
 """
 
+from typing import Protocol
 
-def cocktail_shaker_sort(arr: list[int]) -> list[int]:
+
+class Comparable(Protocol):
+    def __lt__(self, other: object, /) -> bool: ...
+
+
+def cocktail_shaker_sort[T: Comparable](arr: list[T]) -> list[T]:
     """
     Sorts a list using the Cocktail Shaker Sort algorithm.
 
@@ -28,7 +34,12 @@ def cocktail_shaker_sort(arr: list[int]) -> list[int]:
     Traceback (most recent call last):
         ...
     TypeError: 'tuple' object does not support item assignment
-    """
+
+    >>> cocktail_shaker_sort(["elderberry", "banana", "date", "apple", "cherry"])
+    ['apple', 'banana', 'cherry', 'date', 'elderberry']
+    >>> cocktail_shaker_sort([3.2, -1.1, 2.4, 0.5])
+    [-1.1, 0.5, 2.4, 3.2]
+"""
     start, end = 0, len(arr) - 1
 
     while start < end:

tests/test_sorts.py

@@ -96,6 +96,7 @@ def test_sort_matches_builtin(sort, case):
         bubble_sort_iterative,
         bubble_sort_recursive,
         insertion_sort,
+        cocktail_shaker_sort,
     ],
     ids=lambda f: f.__name__,
 )