Merge pull request #817 from chrishkchris/lstm1125

Fix some new LSTM alerts
diff --git a/examples/onnx/densenet121.py b/examples/onnx/densenet121.py
index 7027164..c8a8f95 100644
--- a/examples/onnx/densenet121.py
+++ b/examples/onnx/densenet121.py
@@ -22,7 +22,6 @@
 
 from singa import device
 from singa import tensor
-from singa import autograd
 from singa import sonnx
 import onnx
 from utils import download_model, check_exist_or_download
diff --git a/examples/onnx/shufflenetv1.py b/examples/onnx/shufflenetv1.py
index 2ace96e..139d6d3 100644
--- a/examples/onnx/shufflenetv1.py
+++ b/examples/onnx/shufflenetv1.py
@@ -23,7 +23,6 @@
 
 from singa import device
 from singa import tensor
-from singa import autograd
 from singa import sonnx
 import onnx
 from utils import download_model, check_exist_or_download
diff --git a/examples/onnx/squeezenet.py b/examples/onnx/squeezenet.py
index 09d7708..861550c 100644
--- a/examples/onnx/squeezenet.py
+++ b/examples/onnx/squeezenet.py
@@ -22,7 +22,6 @@
 
 from singa import device
 from singa import tensor
-from singa import autograd
 from singa import sonnx
 import onnx
 from utils import download_model, check_exist_or_download
@@ -56,16 +55,6 @@
     return img, labels
 
 
-def get_image_label():
-    # download label
-    label_url = 'https://s3.amazonaws.com/onnx-model-zoo/synset.txt'
-    with open(check_exist_or_download(label_url), 'r') as f:
-        labels = [l.rstrip() for l in f]
-    image_url = 'https://s3.amazonaws.com/model-server/inputs/kitten.jpg'
-    img = Image.open(check_exist_or_download(image_url))
-    return img, labels
-
-
 class MyModel(sonnx.SONNXModel):
 
     def __init__(self, onnx_model):
diff --git a/python/singa/utils.py b/python/singa/utils.py
index d102771..7dcf8fb 100644
--- a/python/singa/utils.py
+++ b/python/singa/utils.py
@@ -16,7 +16,6 @@
 # =============================================================================
 
 import sys
-import math
 import numpy as np
 import collections