fix import

Author: aplr

lf_toolkit/io/base_server.py

@@ -11,7 +11,7 @@
 from ..preview import Result as PreviewResult
 from ..shared import Params
 from .handler import Handler
-from .handler import JsonRpcHandler
+from .rpc_handler import JsonRpcHandler
 
 
 EvaluationFunction = Callable[