title: Python 2.7: I can't remove worksheets using xlwt.Workbook._Workbook__worksheets
body: <p>I have a workbook containing 12 sheets. I want to create a new file deleting 7 of them.
  However I can't get rid of "OLD FILES", "Licencias" and "HTM". <a href="https://drive.google.com/file/d/0B2AYlge_EK89R3RBVlZDc2NQdWc/edit?usp=sharing" rel="nofollow">Here is a sample of the workbook,</a> and here is my code. Please help me find out what I'm doing wrong. Thanks in advance.</p>
  
  <pre><code>import xlrd, xlwt, xlutils.copy
  
  #open the report, assign it to a variable
  reporteWilly = xlrd.open_workbook('cctable.xls')
  
  #create a writable copy of the report.
  reporteWillyBk = xlutils.copy.copy(reporteWilly)
  
  #Delete the sheets I dont want in the file
  #by accessing the internal of the object xlwt.Workbook._Workbook_worksheets
  #and there I'll specify only the elements I want in the sheets list:
  
  #First I create a list of the worksheets available
  okSheets = reporteWillyBk._Workbook__worksheets
  
  #Then I remove from the list the sheets I don't want.
  for sheet in okSheets:
      if (sheet.name == "Guayaquil" or sheet.name== "Exports" or sheet.name == "OLD FILES" 
          or sheet.name == "Ecuador Holidays 2011" or sheet.name == "Licencias"
          or sheet.name == "FILE LOCATION" or sheet.name == "HTM" ):
  
          okSheets.remove(sheet)
  
  #lastly I assing the good sheets I want to the collection.
  reporteWillyBk._Workbook__worksheets = okSheets
  
  #and save the new workbook.
  reporteWillyBk.save ('cctableWilly.xls')
  </code></pre>