title: Openpyxl update Data Validation
body: <p>I want to create a drop down list in a excel sheet, and be able to update it when I load this sheet. When I change the items in my DataValidation list, and add it to the sheet, the list doesn't change. </p>
  
  <p>Is there a way to update my list or just delete it?</p>
  
  <pre><code>wb = openpyxl.load_workbook(path)
  
  ws_meteo = wb.active
  
  dv = DataValidation(type="list", formula1=Formule, allow_blank=True)
  
  dv.add_cell(ws_meteo['A10'])
  
  ws_meteo.add_data_validation(dv)
  
  wb.save(path)
  </code></pre>