added strict mypy checks

python_utils/__init__.py

@@ -0,0 +1,4 @@
+from .check_env import check_env as check_env
+from .readable_unit import readable_unit as readable_unit
+
+__all__ = ["check_env", "readable_unit"]

python_utils/check_env.py

@@ -5,7 +5,7 @@ import os
 
 
 def check_env(
-    var_list: str | list[str],
+    var_list: str | set[str] | list[str] | tuple[str, ...],
     missing_ok: bool = False,
 ) -> None:
     """Check if environment variables are set.