title: How do I block comment in Jupyter notebook?
body: <p>I want to comment out a block of multiple lines in Jupyter  Notebook, but can't find out how to do that in this current version.<br />
  It used to be in one of the drop down menus but is no longer there.<br />
  How do you comment out multi-line blocks of code at once?</p>
  <p>This is not a duplicate because the solution given in the following link doesn't seem to work anymore:<br />
  <a href="https://stackoverflow.com/questions/19318298/how-can-i-block-comment-code-in-the-ipython-notebook">How can I block comment code in the IPython notebook?</a></p>
  <p><kbd>Ctrl</kbd> + <kbd>/</kbd> does nothing.</p>