I can't repro this, but PR #250 suggests that some versions of
libmagic will return a mimetype that doesn't include a charset,
leading to an exception.  Fall back to an empty charset in this case.

https://github.com/ahupp/python-magic/issues/232

I achieved this via the PyCharm Reformat Shortcut

The libmagic distribution uses the same package name `magic` as
python-magic, but has an incompatible API.  This change merges in a
copy of libmagic's bindings, wrapped to give deprecation warnings.

This is intended to a) mitigate the short-term pain to users and
packagers who need to figure out which to use, and b) give us a path
to merging the two sets of bindings.

I'd be happy for libmagic to take over this package if we could find a
path to it.