Right now, it appears that the version of python3-magic that BitCurator is preferring is not compatible with the script:
/usr/local/lib/python3.5/dist-packages/magic.py
Generates "module 'magic' has no attribute open"
Though if the following version is installed
/usr/lib/python3/dist-packages/magic.py
The script will work. More investigation needed... (more soon!)
Thanks to Jessica Venlet (@jesmven) for reporting.