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/__init__.py b/data_structures/linked_list/__init__.py
index a5f5537b1d96..8d6db4e80ecd 100644
--- a/data_structures/linked_list/__init__.py
+++ b/data_structures/linked_list/__init__.py
@@ -6,28 +6,31 @@
     - Last node: points to null
 """
 
-from typing import Any
+from typing import Generic, Optional, TypeVar
 
+T = TypeVar("T")
 
-class Node:
-    def __init__(self, item: Any, next: Any) -> None:
+
+class Node(Generic[T]):
+    def __init__(self, item: T, next: Optional["Node[T]"]) -> None:
         self.item = item
         self.next = next
 
 
-class LinkedList:
+class LinkedList(Generic[T]):
     def __init__(self) -> None:
-        self.head = None
+        self.head: Optional[Node[T]] = None
         self.size = 0
 
-    def add(self, item: Any) -> None:
+    def add(self, item: T) -> None:
         self.head = Node(item, self.head)
         self.size += 1
 
-    def remove(self) -> Any:
+    def remove(self) -> Optional[T]:
         if self.is_empty():
             return None
         else:
+            assert self.head is not None
             item = self.head.item
             self.head = self.head.next
             self.size -= 1