diff --git a/personal_data/html_util.py b/personal_data/html_util.py
index 91d2b5d..fc02319 100644
--- a/personal_data/html_util.py
+++ b/personal_data/html_util.py
@@ -71,7 +71,11 @@ def has_data_attribute(e) -> bool:
 
 
 def normalize_soup_slightly(
-    soup, classes=True, scripts=True, comments=True, data_attributes=True,
+    soup,
+    classes=True,
+    scripts=True,
+    comments=True,
+    data_attributes=True,
 ):
     """Perform soup normalization."""
     # Little if any content
diff --git a/personal_data/main.py b/personal_data/main.py
index c21bcec..795cfa7 100644
--- a/personal_data/main.py
+++ b/personal_data/main.py
@@ -1,18 +1,12 @@
-import csv
-import datetime
-import decimal
 import inspect
-import io
-from pathlib import Path
 import logging
-from collections.abc import Iterable, Mapping, Sequence
-from decimal import Decimal
+from collections.abc import Sequence
+from pathlib import Path
 
 import requests
 import requests_cache
-from frozendict import frozendict
 
-from . import notification, data
+from . import data, notification
 from .util import *
 
 logger = logging.getLogger(__name__)
diff --git a/personal_data/parse_util.py b/personal_data/parse_util.py
index 868f55f..878b271 100644
--- a/personal_data/parse_util.py
+++ b/personal_data/parse_util.py
@@ -31,7 +31,8 @@ def parse_duration(text: str) -> datetime.timedelta:
 
 def parse_response_datetime(response) -> datetime.datetime:
     return datetime.datetime.strptime(
-        response.headers['Date'], FORMAT_DATE_HEADER,
+        response.headers['Date'],
+        FORMAT_DATE_HEADER,
     ).replace(tzinfo=datetime.UTC)
 
 
diff --git a/personal_data/util.py b/personal_data/util.py
index 4d64b50..b11025a 100644
--- a/personal_data/util.py
+++ b/personal_data/util.py
@@ -2,13 +2,13 @@ import csv
 import datetime
 import decimal
 import io
-import urllib.parse
-from pathlib import Path
 import logging
-from collections.abc import Iterable, Mapping, Sequence, Callable
-from decimal import Decimal
-
 import typing
+import urllib.parse
+from collections.abc import Callable, Iterable, Mapping, Sequence
+from decimal import Decimal
+from pathlib import Path
+
 from frozendict import frozendict
 
 from . import data
@@ -20,14 +20,25 @@ csv.register_dialect(CSV_DIALECT, lineterminator='\n', skipinitialspace=True)
 
 T = typing.TypeVar('T')
 
-def try_value(fn: Callable[[str],T], s: str) -> T | None:
+
+def try_value(fn: Callable[[str], T], s: str) -> T | None:
     try:
         return fn(s)
     except (ValueError, decimal.InvalidOperation):
         return None
 
 
-def to_value(s: str) -> str | Decimal | datetime.date | datetime.datetime | urllib.parse.ParseResult | bool | None:
+def to_value(
+    s: str,
+) -> (
+    str
+    | Decimal
+    | datetime.date
+    | datetime.datetime
+    | urllib.parse.ParseResult
+    | bool
+    | None
+):
     s = s.strip()
     if len(s) == 0:
         return None
@@ -139,6 +150,7 @@ def load_csv_file(csv_file: Path) -> list[frozendict]:
         del csvfile
     return dicts
 
+
 def extend_csv_file(
     csv_file: Path,
     new_dicts: list[dict],
@@ -175,7 +187,7 @@ def extend_csv_file(
     output_csv = csvfile_in_memory.getvalue()
     del writer, csvfile_in_memory
 
-    csv_file.parent.mkdir(parents=True,exist_ok=True)
+    csv_file.parent.mkdir(parents=True, exist_ok=True)
     with open(csv_file, 'w') as csvfile:
         csvfile.write(output_csv)
         del csvfile
diff --git a/personal_data_calendar/__main__.py b/personal_data_calendar/__main__.py
index 373b62f..56171c1 100644
--- a/personal_data_calendar/__main__.py
+++ b/personal_data_calendar/__main__.py
@@ -1,13 +1,13 @@
 import argparse
-import logging
-import icalendar
-import urllib.parse
 import datetime
-import csv
+import urllib.parse
+
+import icalendar
 
 from personal_data.util import load_csv_file
 
-NOW = datetime.datetime.now(tz = datetime.UTC)
+NOW = datetime.datetime.now(tz=datetime.UTC)
+
 
 def parse_arguments():
     parser = argparse.ArgumentParser()
@@ -15,6 +15,7 @@ def parse_arguments():
     parser.add_argument('output_file')
     return parser.parse_args()
 
+
 def generate_calendar(rows: list[dict]) -> icalendar.Calendar:
     cal = icalendar.Calendar()
     cal.add('prodid', '-//personal_data_calendar//example.org//')
@@ -24,9 +25,13 @@ def generate_calendar(rows: list[dict]) -> icalendar.Calendar:
         print(event_data)
 
         # Select data
-        possible_time_keys = [k for k,v in event_data.items() if isinstance(v, datetime.date)]
-        possible_name_keys = [k for k,v in event_data.items() if isinstance(v, str)]
-        possible_image_keys = [k for k,v in event_data.items() if isinstance(v, urllib.parse.ParseResult)]
+        possible_time_keys = [
+            k for k, v in event_data.items() if isinstance(v, datetime.date)
+        ]
+        possible_name_keys = [k for k, v in event_data.items() if isinstance(v, str)]
+        possible_image_keys = [
+            k for k, v in event_data.items() if isinstance(v, urllib.parse.ParseResult)
+        ]
 
         date = event_data[possible_time_keys[0]] if possible_time_keys else None
         title = event_data[possible_name_keys[0]]
@@ -64,5 +69,6 @@ def main():
     with open(args.output_file, 'wb') as f:
         f.write(calendar.to_ical())
 
+
 if __name__ == '__main__':
     main()