title: python-pptx / Updating an existing Powerpoint chart without its excel sheet replacement
body: <p>I have a powerpoint presentation with charts I want to update from python.</p>
  
  <p>Right now I am using <strong>python-pptx</strong> library which is great but its <strong><em>chart.replace_data()</em></strong> the method is replacing the excel sheet with chart data in the chart.</p>
  
  <p>Unfortunately, some of my charts have data labels calculated in separate cells (f.e I am using a normal bar chart but showing % value data labels with additional words in them, which are calculated alongside in excel).</p>
  
  <p>Is there any alternative way to update chart data not affecting other cells of the excel sheet?</p>