Replace typing.optional with new annotations syntax (#5829)

* Replace typing.optional with new annotations syntax

* updating DIRECTORY.md

Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>

data_structures/linked_list/__init__.py

@@ -5,8 +5,9 @@ Nodes contain data and also may link to other nodes:
                  head node gives us access of the complete list
     - Last node: points to null
 """
+from __future__ import annotations
 
-from typing import Any, Optional
+from typing import Any
 
 
 class Node:
@@ -17,7 +18,7 @@ class Node:
 
 class LinkedList:
     def __init__(self) -> None:
-        self.head: Optional[Node] = None
+        self.head: Node | None = None
         self.size = 0
 
     def add(self, item: Any) -> None:

data_structures/linked_list/circular_linked_list.py

@@ -1,10 +1,12 @@
-from typing import Any, Iterator, Optional
+from __future__ import annotations
+
+from typing import Any, Iterator
 
 
 class Node:
     def __init__(self, data: Any):
         self.data: Any = data
-        self.next: Optional[Node] = None
+        self.next: Node | None = None
 
 
 class CircularLinkedList:

data_structures/linked_list/has_loop.py

@@ -1,4 +1,6 @@
-from typing import Any, Optional
+from __future__ import annotations
+
+from typing import Any
 
 
 class ContainsLoopError(Exception):
@@ -8,7 +10,7 @@ class ContainsLoopError(Exception):
 class Node:
     def __init__(self, data: Any) -> None:
         self.data: Any = data
-        self.next_node: Optional[Node] = None
+        self.next_node: Node | None = None
 
     def __iter__(self):
         node = self

data_structures/linked_list/middle_element_of_linked_list.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from __future__ import annotations
 
 
 class Node:
@@ -17,7 +17,7 @@ class LinkedList:
         self.head = new_node
         return self.head.data
 
-    def middle_element(self) -> Optional[int]:
+    def middle_element(self) -> int | None:
         """
         >>> link = LinkedList()
         >>> link.middle_element()