Ugly error message when saving screen grab

[quicklizard99]

Inselect 0.1.35 windows x64 - select `File, Save screen grab...'

File "C:\Users\Lawrence\projects\inselect\inselect\gui\main_window.py", line 637, in save_screengrab
 File "C:\Users\Lawrence\Miniconda3-64\envs\inselect\lib\pprint.py", line 53, in pprint
 File "C:\Users\Lawrence\Miniconda3-64\envs\inselect\lib\pprint.py", line 139, in pprint
 File "C:\Users\Lawrence\Miniconda3-64\envs\inselect\lib\pprint.py", line 176, in _format

AttributeError: 'NoneType' object has no attribute 'write'