title: ImportError when importing metric from sklearn
body: <p>When I am trying to import a metric from sklearn, I get the following error:</p>
  <pre><code>from sklearn.metrics import mean_absolute_percentage_error
  
  ImportError: cannot import name 'mean_absolute_percentage_error' from 'sklearn.metrics'
  
  /Users/carter/opt/anaconda3/lib/python3.8/site-packages/sklearn/metrics/__init__.py)
  </code></pre>
  <p>I have used conda update all, and reinstalled scikit-learn to no avail. Any other reasons this might happen and solutions?</p>