title: re.split() gives empty elements in list
body: <p>please help with this case:</p>
  
  <pre><code>m = re.split('([A-Z][a-z]+)', 'PeopleRobots')
  print (m)
  </code></pre>
  
  <p>Result:</p>
  
  <pre><code>['', 'People', '', 'Robots', '']
  </code></pre>
  
  <p>Why does the list have empty elements?</p>