diff --git a/example/tutorial_tfrecord3.py b/example/tutorial_tfrecord3.py
index 0da7a8b83..b111bf127 100644
--- a/example/tutorial_tfrecord3.py
+++ b/example/tutorial_tfrecord3.py
@@ -15,15 +15,12 @@
 
 """
 
-import io
 import json
 import os
-import time
 import numpy as np
 import tensorflow as tf
 import tensorlayer as tl
 from PIL import Image
-from tensorlayer.layers import set_keep
 
 
 def _int64_feature(value):
@@ -326,7 +323,7 @@ def prefetch_input_data(reader,
 try:
     # for TensorFlow 0.11
     img = tf.image.resize_images(img, size=(resize_height, resize_width), method=tf.image.ResizeMethod.BILINEAR)
-except:
+except Exception:
     # for TensorFlow 0.10
     img = tf.image.resize_images(img, new_height=resize_height, new_width=resize_width, method=tf.image.ResizeMethod.BILINEAR)
 # Crop to final dimensions.
diff --git a/tensorlayer/prepro.py b/tensorlayer/prepro.py
index 85970e9f9..04af4c328 100644
--- a/tensorlayer/prepro.py
+++ b/tensorlayer/prepro.py
@@ -100,8 +100,10 @@ def apply_fn(results, i, data, kwargs):
     if thread_count is None:
         results = [None] * len(data)
         threads = []
-        for i in range(len(data)):
-            t = threading.Thread(name='threading_and_return', target=apply_fn, args=(results, i, data[i], kwargs))
+        # for i in range(len(data)):
+        #     t = threading.Thread(name='threading_and_return', target=apply_fn, args=(results, i, data[i], kwargs))
+        for i, d in enumerate(data):
+            t = threading.Thread(name='threading_and_return', target=apply_fn, args=(results, i, d, kwargs))
             t.start()
             threads.append(t)
     else:
@@ -120,7 +122,7 @@ def apply_fn(results, i, data, kwargs):
     if thread_count is None:
         try:
             return np.asarray(results)
-        except:
+        except Exception:
             return results
     else:
         return np.concatenate(results)