http://hl7.org/fhir/StructureDefinition/computablevalueset|5.0.0

Defines a computable value set as one that SHALL have an expression-based definition (i.e. a value set defined intensionally using expressions of the code systems involved) and MAY have an expansion included. The expression-based definition SHALL be represented in only one of three ways; using the compose element, using the expression extension, or using the rules-text extension to provide a step-by-step process for expanding the value set definition