[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/trie/radix_tree.py

@@ -6,6 +6,7 @@
 with its parent [https://en.wikipedia.org/wiki/Radix_tree]
 """
 
+
 class RadixNode:
     def __init__(self, prefix: str = "", is_leaf: bool = False) -> None:
         # Mapping from the first character of the prefix of the node