-SERVICE. It must provide METHOD. HANDLER is a Lisp function to be
-called when a method call is received. It must accept the input
-arguments of METHOD. The return value of HANDLER is used for
-composing the returning D-Bus message.
+SERVICE. It must provide METHOD.
+
+HANDLER is a Lisp function to be called when a method call is
+received. It must accept the input arguments of METHOD. The return
+value of HANDLER is used for composing the returning D-Bus message.
+In case HANDLER shall return a reply message with an empty argument
+list, HANDLER must return the symbol `:ignore'.