[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/binary_tree_mirror.py

@@ -8,10 +8,11 @@ def mirror_subtree(tree: dict, root: int):
     if right:
         mirror_subtree(tree, right)
 
+
 def mirror_binary_tree(tree: dict, root: int = 1) -> dict:
     """
     Returns the mirror of the given binary tree starting from the root.
-    
+
     >>> mirror_binary_tree({1: [2, 3], 2: [4, 5], 3: [6, 7], 7: [8, 9]}, 1)
     {1: [3, 2], 2: [5, 4], 3: [7, 6], 7: [9, 8]}
     >>> mirror_binary_tree({1: [2, 3], 2: [4, 5], 3: [6, 7], 4: [10, 11]}, 1)
@@ -34,8 +35,10 @@ def mirror_binary_tree(tree: dict, root: int = 1) -> dict:
     mirror_subtree(mirrored_tree, root)
     return mirrored_tree
 
+
 if __name__ == "__main__":
     import doctest
+
     doctest.testmod()
 
     binary_tree = {1: [2, 3], 2: [4, 5], 3: [6, 7], 7: [8, 9]}