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

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Author: pre-commit-ci[bot]

data_structures/binary_tree/red_black_tree.py

@@ -4,6 +4,7 @@
 from collections.abc import Iterator
 from pprint import pformat
 
+
 class RedBlackTree:
     """
     A Red-Black tree, which is a self-balancing BST (binary search