message: Make code Python 2 and 3 compatible
  Update the Python implementation so that both Python 2 and Python 3 environment can execute
diff: @@ -28,7 +28,7 @@ from __future__ import division
  from __future__ import print_function
  import os
  -import urllib
  +from six.moves.urllib.request import urlopen
  import numpy as np
  import tensorflow as tf
  @@ -44,13 +44,13 @@ IRIS_TEST_URL = "http://download.tensorflow.org/data/iris_test.csv"
  def main():
  # If the training and test sets aren't stored locally, download them.
  if not os.path.exists(IRIS_TRAINING):
  - raw = urllib.urlopen(IRIS_TRAINING_URL).read()
  - with open(IRIS_TRAINING, "w") as f:
  + raw = urlopen(IRIS_TRAINING_URL).read()
  + with open(IRIS_TRAINING, "wb") as f:
  f.write(raw)
  if not os.path.exists(IRIS_TEST):
  - raw = urllib.urlopen(IRIS_TEST_URL).read()
  - with open(IRIS_TEST, "w") as f:
  + raw = urlopen(IRIS_TEST_URL).read()
  + with open(IRIS_TEST, "wb") as f:
  f.write(raw)
  # Load datasets.
  @@ -167,7 +167,7 @@ from __future__ import division
  from __future__ import print_function
  import os
  -import urllib
  +from six.moves.urllib.request import urlopen
  import tensorflow as tf
  import numpy as np
  @@ -184,13 +184,13 @@ them.
  ```python
  if not os.path.exists(IRIS_TRAINING):
  - raw = urllib.urlopen(IRIS_TRAINING_URL).read()
  - with open(IRIS_TRAINING,'w') as f:
  + raw = urlopen(IRIS_TRAINING_URL).read()
  + with open(IRIS_TRAINING,'wb') as f:
  f.write(raw)
  if not os.path.exists(IRIS_TEST):
  - raw = urllib.urlopen(IRIS_TEST_URL).read()
  - with open(IRIS_TEST,'w') as f:
  + raw = urlopen(IRIS_TEST_URL).read()
  + with open(IRIS_TEST,'wb') as f:
  f.write(raw)
  ```
  