text: Title: Issue with writing lists to Excel
  Body: #### OS (e.g. Windows 10)
  
  #### Versions of xlwings, Excel and Python (e.g. 0.11.8, Office 365, Python 3.7)
  
  
  I have a data frame 'df' in Python with the following structure and similar data :
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  rowdata1 | 2.33
  -- | --
  rowdata2 | 4.55
  rowdata3 | [1,2,3]
  rowdata4 | []
  
  
  
  </body>
  
  </html>
  I'm using the following code to write to excel
  
  
  ```python
  
  outputs_sheet.range('A1').options(pd.DataFrame).value = df
  ```
  
  This works for the single value entries in the dataframe but doesn't write the list elements to the excel sheet. Any thoughts on why this is occurring and ways to fix this?
  
  
  