title: ImportError: cannot import name 'registry' from 'pandas.core.dtypes.base'
body: <p>I just did a conda install of a few packages to follow a tutorial, and now I can't even import pandas.</p>
  <p>I installed these:</p>
  <pre><code>fake-factory==0.7.2
  Faker==0.7.3
  pytz==2016.7
  tzlocal==1.3.0
  </code></pre>
  <p>And now I get this:</p>
  <pre><code>&gt;&gt;&gt; import pandas
  Traceback (most recent call last):
    File &quot;&lt;stdin&gt;&quot;, line 1, in &lt;module&gt;
    File &quot;C:\ProgramData\Anaconda3\envs\ariel\lib\site-packages\pandas\__init__.py&quot;, line 42, in &lt;module&gt;
      from pandas.core.api import *
    File &quot;C:\ProgramData\Anaconda3\envs\ariel\lib\site-packages\pandas\core\api.py&quot;, line 7, in &lt;module&gt;
      from pandas.core.arrays.integer import (
    File &quot;C:\ProgramData\Anaconda3\envs\ariel\lib\site-packages\pandas\core\arrays\__init__.py&quot;, line 2, in &lt;module&gt;
      from .base import (ExtensionArray,    # noqa
    File &quot;C:\ProgramData\Anaconda3\envs\ariel\lib\site-packages\pandas\core\arrays\base.py&quot;, line 21, in &lt;module&gt;
      from pandas.core import ops
    File &quot;C:\ProgramData\Anaconda3\envs\ariel\lib\site-packages\pandas\core\ops\__init__.py&quot;, line 21, in &lt;module&gt;
      from pandas.core.construction import extract_array
    File &quot;C:\ProgramData\Anaconda3\envs\ariel\lib\site-packages\pandas\core\construction.py&quot;, line 18, in &lt;module&gt;
      from pandas.core.dtypes.base import ExtensionDtype, registry
  ImportError: cannot import name 'registry' from 'pandas.core.dtypes.base' (C:\ProgramData\Anaconda3\envs\ariel\lib\site-packages\pandas\core\dtypes\base.py)
  </code></pre>
  <p>I tried doing a conda update pandas, but to no avail.</p>
  <p>I also just installed luigi, not quite sure when it broke as I installed all the additional packages in one go.</p>