small fix in protocol

scripts/ws_client.py

@@ -181,6 +181,7 @@ class ClientProtocol:
     async def _handle_default(self, name, type, data):
         key, la, df = data['key'], data['la'], data['df']
 
+        if not df.empty:
             columns = ", ".join([str(column) for column in df.columns])
 
             self.logger.info(key)
@@ -275,6 +276,7 @@ async def create_client(
             logger.error("Unexpected error has occurred:")
             logger.exception(e)
 
+            await asyncio.sleep(sleep_time)
             continue