title: Why does tf.Print() does not print in tensorflow
body: <p>The following code does not give any error but does not print the tensor too.</p>
  
  <pre><code>import tensorflow as tf
  import numpy as np
  
  # Some tensor we want to print the value of
  x = tf.placeholder(tf.float32, shape=[2, 2, 2])
  a = np.array([[[1.,1.], [1.,1.]], [[2.,2.], [2.,2.]]])
  
  m = tf.Print(x,[x])
  
  with tf.Session() as sess:
      sess.run(tf.initialize_all_variables())
      m_eval = m.eval(session=sess,feed_dict={x: a})
  </code></pre>
  
  <p>EDIT: after bgshi's reply, I found that in iPython console, the code does print the tensor value. But I'm using iPython notebook. Is there a way to make it displayed in notebook?</p>