How to use the apicurio-data-models.DocumentType.openapi3 function in apicurio-data-models

ruleVersionName(docType: DocumentType): string {
        if (docType == DocumentType.openapi2) {
            return "OpenAPI 2.0";
        }
        if (docType == DocumentType.openapi3) {
            return "OpenAPI 3.x";
        }
        if (docType == DocumentType.asyncapi2) {
            return "AsyncAPI 2.x";
        }
    }

public isOAI30(): boolean {
        return this.document.getDocumentType() === DocumentType.openapi3;
    }

public is3x(): boolean {
        return this.context.ownerDocument().getDocumentType() == DocumentType.openapi3;
    }