title: F-String in mail python
body: <p>when I use f-string to print supplier names, I use this code:</p>
  <pre><code>for i in range(1,10):
      print(f'{df_supplier_number[&quot;SUPPLIER NAME&quot;][i]}')
  </code></pre>
  <p>The result looks like this:</p>
  <pre><code>supplier 1
  supplier 2
  supplier 3
  supplier 4
  supplier 5
  ...
  </code></pre>
  <p>But when using this method to write an email, I does not work.</p>
  <pre><code>for i in range(1,10):
      outlook = win32.Dispatch('outlook.application')
      mail = outlook.CreateItem(0)
      mail.Subject = f'{df_supplier_number[&quot;SUPPLIER NAME&quot;][i]}' + &quot;_test&quot;
      mail.To = &quot;test@mail.com&quot;
      mail.HTMLBody = r&quot;&quot;&quot;
      Hallo,&lt;br&gt;&lt;br&gt;
      test &quot;&quot;&quot;f&quot;{df_supplier_number[i]}&quot;r&quot;&quot;&quot; erstellen:&lt;br&gt;&lt;br&gt;
      Mit dem Text:&lt;br&gt;
      test1 by &quot;&quot;&quot;f&quot;{df_supplier_number[i]}&quot;r&quot;&quot;&quot;.&lt;br&gt;
      Settlement Date Range: 01. November 2020 to 31. October 2021.&lt;br&gt;&lt;br&gt;
      Und dem Betrag:&lt;br&gt;
      &quot;&quot;&quot;f'{round(df_supplier_number[i],2)}'r&quot;&quot;&quot; € (wie in der angehängten Excel-Datei zu erkennen).&lt;br&gt;&lt;br&gt;
      test
      &quot;&quot;&quot;
      mail.Attachments.Add(os.getcwd()+ &quot;\\&quot; + f'{df_number[i]}'&quot;_test.xlsx&quot;)
    
      mail.Send()
  </code></pre>
  <p>Thanks in advance!</p>