1 files changed, 1 insertions, 1 deletions
diff --git a/synapse/_scripts/generate_signing_key.py b/synapse/_scripts/generate_signing_key.py
index bc26d25bfd..3f8f5da75f 100755
--- a/synapse/_scripts/generate_signing_key.py
+++ b/synapse/_scripts/generate_signing_key.py
@@ -20,7 +20,7 @@ from signedjson.key import generate_signing_key, write_signing_keys
 from synapse.util.stringutils import random_string
 
 
-def main():
+def main() -> None:
     parser = argparse.ArgumentParser()
 
     parser.add_argument(