args check in expert command

cccli/command/expert.py

@@ -14,6 +14,8 @@ class Command_expert(Command):
     '''Switch in expert mode'''
 
     def __call__(self, argv):
+        if len(argv) != 1:
+            raise cmdBadArgument()
         h = list(self.printer.history)
         self.printer.history.read(self.cli.settings.get("expert", ""))
         try: