description: This cross-version extension represents MessageDefinition.focus.code from http://hl7.org/fhir/StructureDefinition/MessageDefinition|4.0.1 for use in FHIR R4B. package_name: hl7.fhir.uv.xver-r4.r4b derivation: constraint name: Ext_R4_MessageDefinition_fo_code type: Extension elements: url: base: {max: '1', min: 1, path: Extension.url} pattern: {type: Uri, value: 'http://hl7.org/fhir/4.0/StructureDefinition/extension-MessageDefinition.focus.code'} index: 0 value: base: {max: '1', min: 0, path: 'Extension.value[x]'} short: Type of resource choices: [valueCode] index: 2 valueCode: base: {max: '1', min: 0, path: 'Extension.value[x]'} type: code short: Type of resource choiceOf: value index: 3 package_version: 0.0.1-snapshot-2 class: extension kind: complex-type url: http://hl7.org/fhir/4.0/StructureDefinition/extension-MessageDefinition.focus.code base: http://hl7.org/fhir/StructureDefinition/Extension|4.3.0 version: 0.0.1-snapshot-2 required: [url]