title: Write list of lists to excel file using xlwt
body: <p>I have a list of lists like:</p>
  
  <pre><code>[
  [u'email', u'salutation', u'firstname', u'lastname', u'remarks', None, None, None, None, None],
  [u'harry@harrypotter.com', u'Mr', u'Daniel', u'Radcliffe', u'expecto patronum', None, None, None, None, None],
  [u'snape@harrypotter.com', u'Mr', u'Severus', u'Snape', u'Always', None, None, None, None, None],
  ]
  </code></pre>
  
  <p>I want to insert this to an excel file. It is possible to do so one by one by writing each element.</p>
  
  <pre><code>book = xlwt.Workbook(encoding="utf-8")
  sheet1 = book.add_sheet("Sheet 1")
  
  row = 0
  for l in listdata:
      col = 0
      for e in l:
          if e:
            sheet1.write(row, col, e)
          col+=1
      row+=1
  </code></pre>
  
  <p>But this method does not look very efficient as the each element of the entire list has to be traversed. Is there a more efficient method to do the same in python with <code>xlwt</code>?</p>