title: ImportError: cannot import name 'etree' on Python 3.6
body: <p>I am getting error while running "from lxml import tree" on python3.6</p>
  
  <pre><code>&gt;&gt;&gt; import lxml
  &gt;&gt;&gt; from lxml import etree
  Traceback (most recent call last):
  File "&lt;stdin&gt;", line 1, in &lt;module&gt;
  ImportError: cannot import name 'etree'
  </code></pre>
  
  <p>The same working on python3.4, I have tried many things to troubleshoot as below but didn't success.</p>
  
  <pre><code>python -m pip uninstall lxml
  python -m pip install lxml==3.6.0
  
  pip install -t /usr/local/lib/python3.6/dist-packages lxml==3.6.0
  </code></pre>