[mod] make flake8 happy

tests/trader/test_settings.py

@@ -2,6 +2,7 @@
 Test if database works fine
 """
 import unittest
+
 from vnpy.trader.setting import SETTINGS, get_settings
 
 
@@ -21,4 +22,4 @@ class TestSettings(unittest.TestCase):
 
 
 if __name__ == '__main__':
-    unittest.main()
+    unittest.main()