SEA: do not override write_target method

else it will not wait for is_running

+ fix in playground

frappy/playground.py

@@ -94,6 +94,7 @@ logger = MainLogger()
 
 class Playground(Server):
     def __init__(self, **kwds):  # pylint: disable=super-init-not-called
+        self.name = 'playground'
         for modname, cfg in kwds.items():
             cfg.setdefault('description', modname)
         self.log = logger.log