title: AttributeError: 'module' object has no attribute 'utcnow'
body: <p>When I input the simple code:</p>
  
  <pre><code>import datetime
  datetime.utcnow()
  </code></pre>
  
  <p>, I was given error message:</p>
  
  <pre><code>Traceback (most recent call last):
    File "&lt;pyshell#1&gt;", line 1, in &lt;module&gt;
      datetime.utcnow()
  AttributeError: 'module' object has no attribute 'utcnow'
  </code></pre>
  
  <p>But python's document of <code>utcnow</code> is just here: <a href="https://docs.python.org/library/datetime.html#datetime.datetime.utcnow" rel="noreferrer">https://docs.python.org/library/datetime.html#datetime.datetime.utcnow</a>. Why does <code>utcnow</code> not work in my computer? Thank you!</p>