Invalid reason leaf node

@prefix omop: <https://w3id.org/omop/ontology/> .
@prefix owl: <http://www.w3.org/2002/07/owl#> .
@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .

omop:invalid_reason a owl:DatatypeProperty,
        owl:FunctionalProperty ;
    rdfs:label "Invalid reason"^^xsd:string ;
    rdfs:comment "For Concept Relationship: Reason the relationship was invalidated. Possible values are 'D' (deleted), 'U' (updated) or NULL."@en,
        "For Concept: Reason the Concept was invalidated. Possible values are D (deleted), U (replaced with an update) or NULL when valid_end_date has the default value."@en,
        "For Drug Strength: Reason the concept was invalidated. Possible values are D (deleted), U (replaced with an update) or NULL when valid_end_date has the default value."@en,
        "For Source To Concept Map: Reason the mapping instance was invalidated. Possible values are D (deleted), U (replaced with an update) or NULL when valid_end_date has the default value."@en ;
    rdfs:domain [ a owl:Class ;
            owl:unionOf ( omop:SourceToConceptMap omop:Concept omop:ConceptRelationship omop:DrugStrength ) ] ;
    rdfs:range xsd:string ;
    omop:omop_cdm_name "concept.invalid_reason#354 AS str"^^xsd:string,
        "concept_relationship.invalid_reason#371 AS str"^^xsd:string,
        "drug_strength.invalid_reason#405 AS str"^^xsd:string,
        "source_to_concept_map.invalid_reason#393 AS str"^^xsd:string .