diff --git a/DIRECTORY.md b/DIRECTORY.md
index 2e9942b5bf93..505ae0a26930 100644
--- a/DIRECTORY.md
+++ b/DIRECTORY.md
@@ -274,6 +274,7 @@
     * [Test Send File](https://github.com/TheAlgorithms/Python/blob/master/file_transfer/tests/test_send_file.py)
 
 ## Fractals
+  * [Julia Sets](https://github.com/TheAlgorithms/Python/blob/master/fractals/julia_sets.py)
   * [Koch Snowflake](https://github.com/TheAlgorithms/Python/blob/master/fractals/koch_snowflake.py)
   * [Mandelbrot](https://github.com/TheAlgorithms/Python/blob/master/fractals/mandelbrot.py)
   * [Sierpinski Triangle](https://github.com/TheAlgorithms/Python/blob/master/fractals/sierpinski_triangle.py)
@@ -424,10 +425,12 @@
   * [Binomial Distribution](https://github.com/TheAlgorithms/Python/blob/master/maths/binomial_distribution.py)
   * [Bisection](https://github.com/TheAlgorithms/Python/blob/master/maths/bisection.py)
   * [Ceil](https://github.com/TheAlgorithms/Python/blob/master/maths/ceil.py)
+  * [Check Polygon](https://github.com/TheAlgorithms/Python/blob/master/maths/check_polygon.py)
   * [Chudnovsky Algorithm](https://github.com/TheAlgorithms/Python/blob/master/maths/chudnovsky_algorithm.py)
   * [Collatz Sequence](https://github.com/TheAlgorithms/Python/blob/master/maths/collatz_sequence.py)
   * [Combinations](https://github.com/TheAlgorithms/Python/blob/master/maths/combinations.py)
   * [Decimal Isolate](https://github.com/TheAlgorithms/Python/blob/master/maths/decimal_isolate.py)
+  * [Double Factorial Iterative](https://github.com/TheAlgorithms/Python/blob/master/maths/double_factorial_iterative.py)
   * [Double Factorial Recursive](https://github.com/TheAlgorithms/Python/blob/master/maths/double_factorial_recursive.py)
   * [Entropy](https://github.com/TheAlgorithms/Python/blob/master/maths/entropy.py)
   * [Euclidean Distance](https://github.com/TheAlgorithms/Python/blob/master/maths/euclidean_distance.py)
diff --git a/data_structures/linked_list/middle_element_of_linked_list.py b/data_structures/linked_list/middle_element_of_linked_list.py
index 185c4ccbbb0a..69020ef5dad7 100644
--- a/data_structures/linked_list/middle_element_of_linked_list.py
+++ b/data_structures/linked_list/middle_element_of_linked_list.py
@@ -1,5 +1,8 @@
+from typing import Optional
+
+
 class Node:
-    def __init__(self, data: int) -> int:
+    def __init__(self, data: int) -> None:
         self.data = data
         self.next = None
 
@@ -14,11 +17,11 @@ def push(self, new_data: int) -> int:
         self.head = new_node
         return self.head.data
 
-    def middle_element(self) -> int:
+    def middle_element(self) -> Optional[int]:
         """
         >>> link = LinkedList()
-        >>> link.middle_element()
-        No element found.
+        >>> link.middle_element() is None
+        True
         >>> link.push(5)
         5
         >>> link.push(6)
@@ -53,7 +56,7 @@ def middle_element(self) -> int:
                 slow_pointer = slow_pointer.next
             return slow_pointer.data
         else:
-            print("No element found.")
+            return None
 
 
 if __name__ == "__main__":