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

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

Author: pre-commit-ci[bot]

ciphers/columnar_transposition.py

@@ -26,6 +26,7 @@
     ...
 ValueError: Key must be a non-empty alphabetic string
 """
+
 from __future__ import annotations
 
 

ciphers/skytale_cipher.py

@@ -32,6 +32,7 @@
     ...
 ValueError: Key must be a positive integer
 """
+
 from __future__ import annotations