[pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

Author: pre-commit-ci[bot]

data_structures/binary_tree/red_black_tree.py

@@ -3,6 +3,7 @@
 from collections.abc import Iterator
 from pprint import pformat
 
+
 class RedBlackTree:
     """
     A Red-Black tree, which is a self-balancing BST (binary search
@@ -839,12 +840,13 @@ def main() -> None:
     >>> pytests()
     """
     import doctest
+
     failures, _ = doctest.testmod()
     if failures == 0:
         print("All doctests passed!")
     else:
         print(f"{failures} doctests failed!")
-    
+
     print_results("Rotating right and left", test_rotations())
     print_results("Inserting", test_insert())
     print_results("Searching", test_insert_and_search())
@@ -859,4 +861,4 @@ def main() -> None:
 
 
 if __name__ == "__main__":
-    main()
+    main()