Add a very, very important full stop.

radicale/__main__.py

@@ -111,7 +111,7 @@ def run():
 
 
 def serve(configuration, logger):
-    """Serve radicale from configuration"""
+    """Serve radicale from configuration."""
     # Fork if Radicale is launched as daemon
     if configuration.getboolean("server", "daemon"):
         # Check and create PID file in a race-free manner