Fix lint errors

app/main.py

@@ -1,11 +1,14 @@
 #!/usr/local/bin/python3
 
+"""Main module."""
+
 from app.app import app
 
 
 def main():
+    """Run the app."""
     app.run()
-    
+
 
 if __name__ == "__main__":
     main()