retyped day2, completed days 3 and 4, modified template

day2/common.py

@@ -1,6 +1,3 @@
-from typing import Any
-
-
-def parse(filename: str) -> Any | None:
+def parse(filename: str) -> list[tuple[str, str]]:
     with open(filename) as f:
         return [tuple(a[:-1].split()) for a in f.readlines()]