description: Mark that an invariant represents 'best practice' rule - a rule that implementers may choose to enforce at error level in some or all circumstances. package_name: hl7.fhir.uv.extensions derivation: constraint name: BestPractice type: Extension elements: extension: {index: 0} url: pattern: {type: Uri, value: 'http://hl7.org/fhir/StructureDefinition/elementdefinition-bestpractice'} index: 1 value: choices: [valueBoolean, valueCodeableConcept] index: 3 valueBoolean: {type: boolean, choiceOf: value, index: 4} valueCodeableConcept: {type: CodeableConcept, choiceOf: value, index: 5} package_version: 5.1.0-ballot1 extensions: {} class: extension kind: complex-type url: http://hl7.org/fhir/StructureDefinition/elementdefinition-bestpractice base: http://hl7.org/fhir/StructureDefinition/Extension version: 5.1.0-ballot1 required: [value, valueBoolean, valueCodeableConcept]