title: How to print the result of `tf.data.Dataset.from_tensor_slices`?
body: <p>I'm a new to tensorflow, so I try every single command appeared in the official document. </p>
  
  <p>How can I properly print the result <code>dataset</code>?  Here is my example:</p>
  
  <pre><code>import tensorflow as tf
  import numpy as np
  </code></pre>
  
  <pre><code>sess = tf.Session()
  X = tf.constant([[[1, 2, 3], [3, 4, 5]], [[3, 4, 5], [5, 6, 7]]])
  Y = tf.constant([[[11]], [[12]]])
  dataset = tf.data.Dataset.from_tensor_slices((X, Y))
  
  dataset
  print type(dataset)
  # print help(dataset)
  # print dataset.output_classes
  # print dataset.output_shapes
  </code></pre>