Format before commit formats binary files

For reasons that may seem silly, I am, nonetheless adding some Python Pickle binary files to git repo.  At the same time, I really like the options presented to apply 'Before Commit':

However, if I select 'Reformat code', the binaries are swept up in the reformatting 'fun'.  That doesn't work so gud in the end.  No one can load those reformatted files.  It looks like your formater thinks it has to alter line-ending characters.

Is there way I can the formatter only concern itself with *.py files?