How to pass FileVar to script running in CLI?

[llamafilm]

I have a custom script with a FileVar. This script takes quite a long time to run because it creates thousands of devices, so I'd like to do it in the CLI instead of web browser. I can't find the syntax for this. I've tried:

$ manage.py runscript --loglevel debug --data '{"csv_file": "/home/cfm_small.csv"}' cfm-test.ImportCFM
[2024-04-13 23:52:31,520][ERROR] - Data is not valid:
[2024-04-13 23:52:31,520][ERROR] - 	csv_file: This field is required.

Edit: I just realized running in the web browser works fine, since it continues running after I close the browser.