diff --git a/personal_data/__main__.py b/personal_data/__main__.py
index 437f049..87c3dc2 100644
--- a/personal_data/__main__.py
+++ b/personal_data/__main__.py
@@ -5,8 +5,10 @@ import personal_data.main
 
 
 def parse_arguments():
+    available_scraper_names = personal_data.main.available_scraper_names()
     parser = argparse.ArgumentParser()
-    parser.add_argument('fetchers', metavar='FETCHER', type=str, nargs='+')
+    parser.add_argument('fetchers', metavar='FETCHER', type=str, nargs='+',
+                        choices=available_scraper_names)
     parser.add_argument('--cookiejar', action='store_true')
     return parser.parse_args()
 
diff --git a/personal_data/data.py b/personal_data/data.py
index 510ec0c..27a7d6a 100644
--- a/personal_data/data.py
+++ b/personal_data/data.py
@@ -1,5 +1,6 @@
 import abc
 import dataclasses
+from collections.abc import Iterator
 from enum import Enum
 
 import requests
@@ -33,5 +34,5 @@ class Scraper(abc.ABC):
         return False
 
     @abc.abstractmethod
-    def scrape(self):
+    def scrape(self) -> Iterator[object]:
         pass
diff --git a/personal_data/main.py b/personal_data/main.py
index 5f5ae89..4dabcf4 100644
--- a/personal_data/main.py
+++ b/personal_data/main.py
@@ -1,4 +1,5 @@
 import csv
+from collections.abc import Iterator
 import datetime
 import io
 import logging
@@ -176,8 +177,14 @@ def send_notification(
         body.append(f'{k}: {v}\n')
     mailgun.send_email(session, f'Updated {scraper_name}', ''.join(body))
 
+def available_scrapers() -> list[type[personal_data.data.Scraper]]:
+    return personal_data.data.Scraper.__subclasses__()
 
-def main(scraper_filter: frozenset[str], use_cookiejar: bool):
+def available_scraper_names() -> list[str]:
+    return [scraper_cls.__name__ for scraper_cls in available_scrapers()]
+
+
+def main(scraper_filter: frozenset[str], use_cookiejar: bool) -> None:
     if use_cookiejar:
         cookiejar = browsercookie.firefox()
         logger.info('Got cookiejar from firefox: %s cookies', len(cookiejar))
@@ -185,7 +192,7 @@ def main(scraper_filter: frozenset[str], use_cookiejar: bool):
         cookiejar = []
         logger.warning('No cookiejar is used')
 
-    for scraper_cls in personal_data.data.Scraper.__subclasses__():
+    for scraper_cls in available_scrapers():
         session = get_session(cookiejar, with_cfscrape=scraper_cls.requires_cfscrape())
         scraper = scraper_cls(session)
         if scraper_cls.__name__ not in scraper_filter:
@@ -195,7 +202,7 @@ def main(scraper_filter: frozenset[str], use_cookiejar: bool):
             scraper_cls.__name__,
             scraper.dataset_name,
         )
-        result_rows = list()
+        result_rows = []
         try:
             for result in scraper.scrape():
                 result_rows.append(result)