title: Openpyxl : the load_workbook function was automatically called when the open function run
body: <p>the code as below</p>
  <pre><code>from openpyxl import *
  wb = load_workbook(r'./test.xlsx')
  ws = wb.active
  ws1 = wb.create_sheet(&quot;Mysheet&quot;)
  ws.delete_cols(2)
  wb.save('./test.xlsx')
  tagui_output = open('C:/Downloads/TagUI_Windows/tagui/src/tagui_py/tagui_py.txt','w')
  tagui_output.write(temp_result)
  tagui_output.close()
  </code></pre>
  <p>the output of code as below</p>
  <pre><code>C:\Downloads\TagUI_Windows\tagui\flows\samples&gt; python .\excel2.py
  fn of load_workbook = ./test.xlsx
  fn of load_workbook = C:/Downloads/TagUI_Windows/tagui/src/tagui_py/tagui_py.txt
  Traceback (most recent call last):
    File &quot;C:\Downloads\TagUI_Windows\tagui\flows\samples\excel2.py&quot;, line 7, in &lt;module&gt;
      tagui_output = open('C:/Downloads/TagUI_Windows/tagui/src/tagui_py/tagui_py.txt','w')
    File &quot;C:\Users\xxx\AppData\Local\Programs\Python\Python39\lib\site-packages\openpyxl\reader\excel.py&quot;, line 316, in load_workbook
      reader = ExcelReader(filename, read_only, keep_vba,
    File &quot;C:\Users\xxx\AppData\Local\Programs\Python\Python39\lib\site-packages\openpyxl\reader\excel.py&quot;, line 124, in __init__
      self.archive = _validate_archive(fn)
    File &quot;C:\Users\xxx\AppData\Local\Programs\Python\Python39\lib\site-packages\openpyxl\reader\excel.py&quot;, line 94, in _validate_archive
      raise InvalidFileException(msg)
  openpyxl.utils.exceptions.InvalidFileException: filename=C:/Downloads/TagUI_Windows/tagui/src/tagui_py/tagui_py.txt openpyxl does not support .txt file format, please check you can open it with Excel first. Supported formats are: .xlsx,.xlsm,.xltx,.xltm
  </code></pre>
  <p>It seems the load_workbook function was automatically called when the open('C:/Downloads/TagUI_Windows/tagui/src/tagui_py/tagui_py.txt','w') function run,why this  happened ?</p>