it occurred to me that rather than migrating ILS charges by creating FOLIO loans, aka POSTing to /circulation/loans, it might be less complicated to simply check the relevant items out to the relevant borrowers via /circulation/check-out-by-barcode and follow up with /circulation/loans/{id}/change-due-date to modify due dates as needed
one of the benefits of this approach was the opportunity to test the circ rules to make sure that I had gotten them right 
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