diff --git a/lectures/pandas/PublicAPIs.ipynb b/lectures/pandas/PublicAPIs.ipynb
index 1c80de7..65b02ac 100644
--- a/lectures/pandas/PublicAPIs.ipynb
+++ b/lectures/pandas/PublicAPIs.ipynb
@@ -3320,9 +3320,9 @@
    "source": [
     "url = \"https://api.met.no/weatherapi/locationforecast/2.0/compact?lat=51.5&lon=0\"\n",
     "s = requests.Session()\n",
-    "s.headers[\n",
-    "    \"User-Agent\"\n",
-    "] = \"uio-in3110 https://github.com/uio-in3110/uio-in3110.github.io\"\n",
+    "s.headers[\"User-Agent\"] = (\n",
+    "    \"uio-in3110 https://github.com/uio-in3110/uio-in3110.github.io\"\n",
+    ")\n",
     "r = s.get(url)\n",
     "r"
    ]
diff --git a/lectures/production/from-script-to-project/monty-hall-game4/monty_hall_game/__main__.py b/lectures/production/from-script-to-project/monty-hall-game4/monty_hall_game/__main__.py
index 27d14a7..9ae637f 100644
--- a/lectures/production/from-script-to-project/monty-hall-game4/monty_hall_game/__main__.py
+++ b/lectures/production/from-script-to-project/monty-hall-game4/monty_hall_game/__main__.py
@@ -1,4 +1,4 @@
 from .cli import main
 
 if __name__ == "__main__":
-    main()
\ No newline at end of file
+    main()
diff --git a/lectures/python/exercises.ipynb b/lectures/python/exercises.ipynb
index 0bc0490..a26d0c0 100644
--- a/lectures/python/exercises.ipynb
+++ b/lectures/python/exercises.ipynb
@@ -404,8 +404,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "class Square(...):\n",
-    "    ...\n",
+    "class Square(...): ...\n",
     "\n",
     "\n",
     "sq = Square(5)\n",