This is the CodeSystem that contains all the codes in Codes for insurance item type (http://hl7.org/fhir/us/davinci-drug-formulary/CodeSystem/usdf-InsuranceItemTypeCS) and Codes for insurance item type (http://hl7.org/fhir/us/davinci-drug-formulary/CodeSystem/usdf-InsuranceItemTypeCS). E.g. what you have to deal with if you get resources containing codes in either of them