minor changes to merge into release-1.4 (#2069)

* fix bugs and add python3 supports
* minor changes

PaddleCV/human_pose_estimation/README_cn.md

@@ -89,7 +89,7 @@ python val.py --dataset 'mpii' --checkpoint 'checkpoints/pose-resnet50-mpii-384x
 ### 模型训练
 
 ```bash
-python train.py --dataset 'mpii' --data_root 'data/mpii'
+python train.py --dataset 'mpii'
 ```
 
 **说明** 详细参数配置已保存到`lib/mpii_reader.py` 和 `lib/coco_reader.py`文件中，通过设置dataset来选择使用具体的参数配置

PaddleCV/human_pose_estimation/utils/utility.py

@@ -41,7 +41,7 @@ def print_arguments(args):
     :type args: argparse.Namespace
     """
     print("-----------  Configuration Arguments -----------")
-    for arg, value in sorted(vars(args).iteritems()):
+    for arg, value in sorted(vars(args).items()):
         print("%s: %s" % (arg, value))
     print("------------------------------------------------")