added doctests and typehints

Author: shrabian

sorts/recursive_insertion_sort.py

@@ -2,12 +2,14 @@
 A recursive implementation of the insertion sort algorithm
 """
 
-def rec_insertion_sort(collection, n):
+from typing import List
+
+def rec_insertion_sort(collection: List, n: int):
     """
     Given a collection of numbers and its length, sorts the collections
     in ascending order
 
-    :param collection: A mutable collection of heterogenous, comparable elements
+    :param collection: A mutable collection of comparable elements
     :param n: The length of collections
 
     >>> col = [1, 2, 1]
@@ -25,18 +27,33 @@ def rec_insertion_sort(collection, n):
     >>> print(col)
     [1]
     """
-
-
     #Checks if the entire collection has been sorted
     if len(collection) <= 1 or n <= 1:
         return
 
 
-    data_swap(collection, n-1)
+    insert_next(collection, n-1)
     rec_insertion_sort(collection, n-1)
 
-def data_swap(collection, index):
+def insert_next(collection: List, index: int):
+    """
+    Inserts the '(index-1)th' element into place
+
+    >>> col = [3, 2, 4, 2]
+    >>> insert_next(col, 1)
+    >>> print(col)
+    [2, 3, 4, 2]
+
+    >>> col = [3, 2, 3]
+    >>> insert_next(col, 2)
+    >>> print(col)
+    [3, 2, 3]
 
+    >>> col = []
+    >>> insert_next(col, 1)
+    >>> print(col)
+    []
+    """
     #Checks order between adjacent elements
     if index >= len(collection) or collection[index - 1] <= collection[index]:
         return
@@ -46,7 +63,7 @@ def data_swap(collection, index):
     collection[index], collection[index - 1]
     )
 
-    data_swap(collection, index + 1)
+    insert_next(collection, index + 1)
 
 if __name__ == "__main__":
     numbers = input("Enter integers seperated by spaces: ")