diff --git a/stressor/__init__.py b/stressor/__init__.py
index 06f72b6..077d70e 100644
--- a/stressor/__init__.py
+++ b/stressor/__init__.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 Current version number.
 
@@ -15,5 +14,6 @@
     When pywin32 is installed, number must be a.b.c for MSI builds?
     "3.0.0a4" seems not to work in this case!
 """
+
 # flake8: noqa
 __version__ = "0.5.3-a1"
diff --git a/stressor/config_manager.py b/stressor/config_manager.py
index 7bb2a5d..eade6dc 100644
--- a/stressor/config_manager.py
+++ b/stressor/config_manager.py
@@ -231,9 +231,14 @@ def _check_type(key, types):
             return True
 
         sections = set(cfg.keys())
-        known_sections = set(
-            ("file_version", "config", "context", "sessions", "scenario", "sequences")
-        )
+        known_sections = {
+            "file_version",
+            "config",
+            "context",
+            "sessions",
+            "scenario",
+            "sequences",
+        }
 
         file_version = cfg.get("file_version", "")
         if not file_version.startswith("stressor#"):