diff --git a/clean.py b/clean.py
index 1cbecbf..3cb6707 100644
--- a/clean.py
+++ b/clean.py
@@ -2,33 +2,19 @@ import csv
 import json
 from datetime import datetime
 from pathlib import Path
+from typing import Generator
 
 
-def json_to_daily_pkg(
-    input_dir: Path, output_dir: Path, force: bool = False
-) -> int | None:
+def json_to_daily_pkg(input_dir: Path, output_dir: Path, force: bool = False) -> None:
     if not input_dir.is_dir():
         raise ValueError
     output_dir.mkdir(exist_ok=True, parents=True)
 
     # only clean if raw files have been updated since last time
-    if not force:
-        last_raw_update: datetime = datetime(1, 1, 1)
-        oldest_clean: datetime = datetime.now()
-        for file in input_dir.glob("*.json"):
-            mdate = datetime.fromtimestamp(file.stat().st_mtime)
-            if mdate > last_raw_update:
-                last_raw_update = mdate
-        for file in output_dir.glob("*.csv"):
-            mdate = datetime.fromtimestamp(file.stat().st_mtime)
-            if mdate < oldest_clean:
-                oldest_clean = mdate
-        if oldest_clean > last_raw_update:
-            print(
-                "INFO: Skip creating cleaned data,"
-                f" last processing {oldest_clean} newer than {last_raw_update}"
-            )
-            return
+    if not force and not newer_than_last_clean(
+        input_dir.glob("*.json"), output_dir.glob("*.csv"), desc="daily packages"
+    ):
+        return
 
     for j in input_dir.glob("*.json"):
         with open(j) as fr:
@@ -55,6 +41,29 @@ def json_to_daily_pkg(
                     # print(output_file, p_date, p_name, p_count)
 
 
+def newer_than_last_clean(
+    input_glob: Generator, output_glob: Generator, desc: str | None = None
+) -> bool:
+    last_raw_update: datetime = datetime(1, 1, 1)
+    oldest_clean: datetime = datetime.now()
+    for file in input_glob:
+        mdate = datetime.fromtimestamp(file.stat().st_mtime)
+        if mdate > last_raw_update:
+            last_raw_update = mdate
+    for file in output_glob:
+        mdate = datetime.fromtimestamp(file.stat().st_mtime)
+        if mdate < oldest_clean:
+            oldest_clean = mdate
+    if oldest_clean > last_raw_update:
+        print(
+            "INFO: Skip creating cleaned data"
+            f"{f' for {desc}' if desc else ''}"
+            f", last processing {oldest_clean} newer than {last_raw_update}"
+        )
+        return False
+    return True
+
+
 def main(input: str, output: str) -> None:
     json_to_daily_pkg(Path(input) / "daily", Path(output) / "daily", force=True)