title: How to keep style format unchanged after writing data using OpenPyXL package in Python?
body: <p>I'm using <code>openpyxl</code> library package to read and write some data to an existing excel file <code>test.xlsx</code>.</p>
  
  <p>Before writing some data to it, the content of file look like this:</p>
  
  <p><a href="https://i.stack.imgur.com/lLoLM.png" rel="noreferrer"><img src="https://i.stack.imgur.com/lLoLM.png" alt="enter image description here"></a></p>
  
  <ul>
  <li><p>cell A1 is contain Khmer Unicode character, and English character is in <strong>Bold</strong> style.</p></li>
  <li><p>cell A3 used font <a href="https://khmersoft.net/download-font-limon-khmer-font-for-your-computer/" rel="noreferrer">lemons1</a> font-face, and English character is in <em>Italic</em> style.</p></li>
  </ul>
  
  <p>I was using the script below to read and write data "It is me" to cell B2  of this excel file:</p>
  
  <pre><code>from openpyxl import load_workbook
  import os
  FILENAME1 = os.path.dirname(__file__)+'/test.xlsx'
  from flask import make_response
  from openpyxl.writer.excel import save_virtual_workbook
  from app import app
  
  @app.route('/testexel', methods=['GET'])
  def testexel():
      with app.app_context():
          try:
              filename = 'test'
              workbook = load_workbook(FILENAME1, keep_links=False)
              sheet = workbook['Sheet1']
              sheet['B2']='It is me'
  
              response = make_response(save_virtual_workbook(workbook))
              response.headers['Cache-Control'] = 'no-cache'
              response.headers["Content-Disposition"] = "attachment; filename=%s.xlsx" % filename
              response.headers["Content-type"] = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet; charset=utf-8"
  
              return response
  
          except Exception as e:
  
              raise
  </code></pre>
  
  <p>Then format of resulted excel file was modified as this, which I've never wanted it to be like this :</p>
  
  <p><a href="https://i.stack.imgur.com/SWsuB.png" rel="noreferrer"><img src="https://i.stack.imgur.com/SWsuB.png" alt="enter image description here"></a> </p>
  
  <p>The formatting style is quite different from the original file before writing data to it:</p>
  
  <ul>
  <li><p>cell A1 all data is all bold taking style format from English character</p></li>
  <li><p>cell B3 English character became a normal style, and font was change to font-face <code>limons1</code> taking from that of khmer character in front of it.</p></li>
  </ul>
  
  <p><strong>What I am trying to accomplish</strong> is to keep existing content of file in the same format (style and font-face) as it was, while writing additional data to it.</p>
  
  <p>Please kindly advise what is wrong with my script and how can I do to keep existing style and font-face unchanged after running above script? Thanks.</p>