title: Excel wont recognize date using openpyxl
body: <p>I have a piece of code that converts a unix date to standard U.S. date format. It displays properly in excel, however excel doesn't recognize it as a date.</p>
  
  <pre><code>if str(startdate).isdigit():
      startdate = int(startdate)
      date = datetime.datetime.fromtimestamp(int(startdate)).strftime('%m/%d/%Y')
      ws4.cell(row=cell.row,column=2).value = date
      ws4.cell(row=cell.row,column=2).number_format = 'MM DD YYYY'
  </code></pre>
  
  <p>Any idea how to get excel to see this as a date rather than text?</p>