title: ImportError: cannot import name 'LatentDirichletAllocation' from 'sklearn.decomposition._online_lda'
body: <p>I'm facing error whenever I import any Tree module from sklearn. Sample code below</p>
  
  <pre><code>from sklearn.ensemble import ExtraTreesRegressor
  model = ExtraTreesRegressor()
  model.fit(X,y)
  </code></pre>
  
  <p>The first time I run the code I get this error - </p>
  
  <pre><code>ImportError: cannot import name 'LatentDirichletAllocation' from 'sklearn.decomposition._online_lda' (C:\Users\lenovo\Anaconda3\lib\site-packages\sklearn\decomposition_online_lda.cp37-win_amd64.pyd)
  </code></pre>
  
  <p>After that, whenever I run the same code, I get the following error - </p>
  
  <pre><code>AttributeError: type object 'sklearn.tree.criterion.array' has no attribute 'reducecython'
  </code></pre>
  
  <p>The same code worked well before but suddenly it has stopped working for me</p>
  
  <p>I've tried uninstalling and re-installing scikit-learn as well. Any help would be appreciated. Thanks :)</p>