title: NameError: name 'sess' is not defined
body: <p>I am running python program under tensorflow. When I input sess.run(),the command line prompt me that NameError: name 'sess' is not defined</p>
  
  <pre><code>print(sess.run(W_conv1))
  Traceback (most recent call last):
  
    File "&lt;ipython-input-17-cf7d3892efbb&gt;", line 1, in &lt;module&gt;
      print(sess.run(W_conv1))
  
  NameError: name 'sess' is not defined
  </code></pre>