title: Timegrouper part of pandas
body: <p>Does TimeGrouper still exist?</p>
  
  <pre><code>print(pd.__version__)
  
  0.25.0
  </code></pre>
  
  <p>This used to work:</p>
  
  <pre><code>tg = pd.TimeGrouper(freq='M')
  </code></pre>
  
  <p>Now it gives</p>
  
  <pre><code>AttributeError: module 'pandas' has no attribute 'TimeGrouper'
  </code></pre>