Type recursive quick sort for any comparable items

Part of #15234

Author: HarshRajSinghania

sorts/recursive_quick_sort.py

@@ -1,19 +1,56 @@
-def quick_sort(data: list) -> list:
-    """
-    >>> for data in ([2, 1, 0], [2.2, 1.1, 0], "quick_sort"):
+"""
+A pure Python implementation of a recursive quick sort.
+
+For doctests run the following command:
+    python3 -m doctest -v recursive_quick_sort.py
+
+For manual testing run:
+    python3 recursive_quick_sort.py
+"""
+
+from typing import Any, Protocol
+
+
+class Comparable(Protocol):
+    def __lt__(self, other: Any, /) -> bool: ...
+
+
+def quick_sort[T: Comparable](data: list[T]) -> list[T]:
+    """Sort a list of mutually comparable items with recursive quick sort.
+
+    Returns a new list. Items must be mutually orderable. Mixing types that
+    cannot be compared raises ``TypeError`` instead of returning a silently
+    wrong order.
+
+    Examples:
+    >>> quick_sort([2, 1, 0])
+    [0, 1, 2]
+    >>> quick_sort([2.2, 1.1, 0])
+    [0, 1.1, 2.2]
+    >>> quick_sort(["c", "a", "b"])
+    ['a', 'b', 'c']
+    >>> quick_sort([])
+    []
+    >>> quick_sort([2.5, -1, 0.0]) == sorted([2.5, -1, 0.0])
+    True
+    >>> quick_sort(list("quick_sort")) == sorted("quick_sort")
+    True
+    >>> import pytest
+    >>> with pytest.raises(TypeError):
+    ...     quick_sort([1, "a"])
+    >>> for data in ([2, 1, 0], [2.2, 1.1, 0], list("quick_sort")):
     ...     quick_sort(data) == sorted(data)
     True
     True
     True
     """
     if len(data) <= 1:
         return data
-    else:
-        return [
-            *quick_sort([e for e in data[1:] if e <= data[0]]),
-            data[0],
-            *quick_sort([e for e in data[1:] if e > data[0]]),
-        ]
+    return [
+        *quick_sort([item for item in data[1:] if item <= data[0]]),
+        data[0],
+        *quick_sort([item for item in data[1:] if item > data[0]]),
+    ]
 
 
 if __name__ == "__main__":