title: How to add a new work sheet to work book in xlsxwriter
body: <p>I want to add some sheets to one workbook.</p>
  
  <pre><code>sheets = ["A.csv", "B.csv", "C.csv"]
  for sh in sheets:
      workbook = xlsxwriter.Workbook('myxlsx.xlsx')
      worksheet = workbook.add_worksheet(sh)
      worksheet.write(1,1,"abcd")
      workbook.close()
  </code></pre>
  
  <p>But what it does is it only creates a sheet corresponding to "C.csv" and not to "A.csv" and "B.csv"
  From what I have got, it is because every time it loops it creates a new workbook. I want to create the 3 sheets on same workbook.</p>
  
  <p>Also, there is one condition, I want to initialise the workbook constructor inside the loop only.</p>