Error calling importer method: exceptions must derive from BaseException

[gary-roach]

I created a custom importer to import credit card transactions from a pdf. The importer is based on pdfreader. It works fine when calling bean-identify and bean-extract from the command line, but when I attempt to go to the import page on Fava, I get the error message Error calling importer method: exceptions must derive from BaseException.

I'm not sure how to troubleshoot this in Fava. Is there logs somewhere I can look at? Is this something anyone has seen before when building custom importers? Does Fava have any requirements for importers outside of what would be needed to run bean-identify and bean-extract?