title: unnecessary "['', '']" when parse CSV files using python csv module
body: <p>everyone.</p>
  
  <p>I want to parse a csv <code>"20568078","240431","jpg","St, Carolina 1920",,</code>into <code>["20568078","240431","jpg","St, Carolina 1920","",""]</code></p>
  
  <p>by using this:</p>
  
  <pre><code>string=r'"20568078","240431","jpg","St, Carolina 1920",,'
  reader = csv.reader(string)
  for r in reader:
      print (r)
  </code></pre>
  
  <p>I got the output:</p>
  
  <pre><code>['20568078']
  ['', '']
  ['240431']
  ['', '']
  ['jpg']
  ['', '']
  ['St, Carolina 1920']
  ['', '']
  ['', '']
  </code></pre>
  
  <p>I want to konw how to delete the unnecessary <code>['', '']</code>, and change the last two <code>,,</code> to <code>""</code> and <code>""</code> </p>
  
  <p>Thank you.</p>