fix the blank lines

Author: Yuchen Nie

tests/conftest.py

@@ -163,10 +163,12 @@ def mxnet_eia_py_version(mxnet_eia_version, request):
     else:
         return "py3"
 
+
 @pytest.fixture(scope="module")
 def mxnet_eia_latest_py_version():
     return "py3"
 
+
 @pytest.fixture(scope="module", params=["py2", "py3"])
 def pytorch_training_py_version(pytorch_training_version, request):
     if Version(pytorch_training_version) < Version("1.5.0"):