{description: Accesses the active period of a FormularyItem, package_name: hl7.fhir.us.davinci, name: USDFBasicPeriod, type: date, package_version: drug-formulary-2.0.1, class: unknown, kind: null, url: 'http://hl7.org/fhir/us/davinci-drug-formulary/SearchParameter/Basic-period', version: 2.0.1}