title: Python check if list only contains either empty elements or whitespace
body: <p>I would like to check if a list only contains either empty elements or whitespace, something like:</p>
  
  <pre><code>l = ['','   ','\n']
  if all(whitespace or empty for element in l):
      return True
  </code></pre>
  
  <p>Anyone know how to do this?</p>