[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/linked_list/circular_linked_list.py

@@ -144,4 +144,5 @@ def test_circular_linked_list() -> None:
 
 if __name__ == "__main__":
     import doctest
+
     doctest.testmod()