title: Openpyxl - background color isn't saved in file
body: <p>My Python script is supposed to check, whether a certain string is included in a cell. If this condition matches, the script shall change the background color of a cell in another file.
  This process is repeated several times in a for-loop</p>
  
  <pre><code>from openpyxl.styles import PatternFill
  column_color = sheet_database.cell(row = nextitem , column = 18).value
              cell_paint = sheet_blatt.cell(row = 7 + multiplicator * 10 , column = selected_column + 1).fill
              if column_color == 'AAAAAA':
                   cell_paint = PatternFill(fgColor='C00000', bgColor='C00000', fill_type='solid')
  
              elif column_color == 'BBBBBB':
                   cell_paint = PatternFill(fgColor='FF0000', bgColor='FF0000', fill_type='solid')
  </code></pre>
  
  <p>For some reason, the color is not saved to the file in the end.
  The rest of the script just changes values of cells, so the color can not be overwritten by another part of the script.
  Also, the debugger shows, that the if clause is being entered and executed.</p>
  
  <pre><code>wb_blatt.save('XXXX_' + str(number) + '.xlsx')
  </code></pre>
  
  <p>is used to save the final result.</p>