fix codestyle

python/examples/fit_a_line/test_server.py

@@ -16,6 +16,7 @@
 from paddle_serving_server.web_service import WebService
 import numpy as np
 
+
 class UciService(WebService):
     def preprocess(self, feed=[], fetch=[]):
         feed_batch = []
@@ -27,6 +28,7 @@ class UciService(WebService):
         feed = {"x": new_data}
         return feed, fetch, is_batch
 
+
 uci_service = UciService(name="uci")
 uci_service.load_model_config("uci_housing_model")
 uci_service.prepare_server(workdir="workdir", port=9292)