title: opencv installation recursion
body: <p>I am using Ubuntu (18.04.3LTS) and Anaconda for Python. 
  I am trying to install opencv and I followed the installation tutorial.
  But when I type:</p>
  
  <pre><code>    import opencv
      import cv2
  </code></pre>
  
  <p>I get:</p>
  
  <pre><code>['/home/amyuval', '/home/amyuval/anaconda3/lib/python37.zip', '/home/amyuval/anaconda3/lib/python3.7', '/home/amyuval/anaconda3/lib/python3.7/lib-dynload', '', '/home/amyuval/anaconda3/lib/python3.7/site-packages', '/home/amyuval/anaconda3/lib/python3.7/site-packages/IPython/extensions', '/home/amyuval/.ipython']
  </code></pre>
  
  <hr>
  
  <pre><code>ImportError Traceback (most recent call last)
  &lt;ipython-input-3-c8ec22b3e787&gt; in &lt;module&gt;
       1 import cv2
  
  ~/anaconda3/lib/python3.7/cv2/__init__.py in &lt;module&gt;
       87     if DEBUG: print('OpenCV loader: DONE')
       88 
       89 bootstrap()
  
  ~/anaconda3/lib/python3.7/cv2/__init__.py in bootstrap()
       21     if hasattr(sys, 'OpenCV_LOADER'):
       22         print(sys.path)
       23         raise ImportError('ERROR: recursion is detected during loading of "cv2" binary extensions. Check OpenCV installation.')
       24     sys.OpenCV_LOADER = True
       25 
  
  ImportError: ERROR: recursion is detected during loading of "cv2" binary extensions. Check OpenCV installation.
  </code></pre>
  
  <p>What could be the problem?</p>