diff --git a/data_structures/binary_tree/avl_tree.py b/data_structures/binary_tree/avl_tree.py
index a54606026..b008b69cf 100644
--- a/data_structures/binary_tree/avl_tree.py
+++ b/data_structures/binary_tree/avl_tree.py
@@ -201,7 +201,7 @@ def get_balance(node: MyNode | None) -> int:
     return get_height(node.get_left()) - get_height(node.get_right())
 
 
-def get_min_value_node(node: MyNode) -> MyNode:
+def get_min_value_node(node: MyNode | None) -> MyNode | None:
     if node is None:
         return None
     current_node = node
@@ -209,7 +209,6 @@ def get_min_value_node(node: MyNode) -> MyNode:
         current_node = current_node.get_left()
     return current_node
 
-
 def del_node(root: MyNode | None, data: Any) -> MyNode | None:
     if root is None:
         print("Nothing to delete")
@@ -370,4 +369,4 @@ if __name__ == "__main__":
     random.shuffle(lst)
     for i in lst:
         t.del_node(i)
-        print(str(t))
+        print(str(t))
\ No newline at end of file