fix sys error (#4437)

PaddleNLP/pretrain_langauge_models/BERT/utils/args.py

@@ -17,6 +17,7 @@ from __future__ import absolute_import
 from __future__ import division
 from __future__ import print_function
 
+import sys
 import six
 import argparse
 

PaddleNLP/pretrain_langauge_models/XLNet/utils/args.py

@@ -17,6 +17,7 @@ from __future__ import absolute_import
 from __future__ import division
 from __future__ import print_function
 
+import sys
 import six
 import argparse