title: Remove strings containing only white spaces from list
body: <p>How do I delete empty strings from a list? I tried like this:</p>
  
  <pre><code>starring = ['Vashu Bhagnani', 'Khemchand Bhagnani', ' ', 'Jacky Bhagnani', ' ', 'Prashant Shah', ' ']
  output = filter(bool, starring)
  </code></pre>
  
  <p>Output I want:</p>
  
  <pre><code>['Vashu Bhagnani', 'Khemchand Bhagnani',  'Jacky Bhagnani',  'Prashant Shah']
  </code></pre>
  
  <p>But <code>output</code> ends up being the same as <code>input</code>. What's the correct function to pass to <code>filter</code>?</p>