title: Cannot execute code in some of Jupyiter ipython notebook cells
body: <p>Any cells in Jupyter which have <code>In [*]</code> in front of them are not executing in Jupyter notebook. See image below:</p>
  
  <p><a href="https://i.stack.imgur.com/8geSB.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/8geSB.png" alt="enter image description here"></a></p>
  
  <p>I even restarted the kernel, without any improvement of the situation. Previous cells run without trouble. Every cell I added recently has the problem. </p>