title: openpyxl.load_workbook function won't return class - "No such file or directory" error despite it being in right directory
body: <p>I'm trying to return the class of my Excel document, but it won't. The error that I get is <code>FileNotFoundError: [Errno 2] No such file or directory: 'wellbeing.xlsx'</code> despite the fact that I have changed to the right directory. Here is my code.</p>
  
  <pre><code>import openpyxl
  import os
  os.chdir('C:\\Users\\Simon\\Desktop')
  wb = openpyxl.load_workbook('wellbeing.xlsx')
  type(wb)
  </code></pre>