How to use the @accordproject/concerto-core.ModelUtil.getNamespace function in @accordproject/concerto-core

toXsType(type) {
        switch(type) {
        case 'DateTime':
            return 'xs:dateTime';
        case 'Boolean':
            return 'xs:boolean';
        case 'String':
            return 'xs:string';
        case 'Double':
            return 'xs:double';
        case 'Long':
            return 'xs:long';
        case 'Integer':
            return 'xs:integer';
        default:
            return `${ModelUtil.getNamespace(type)}:${ModelUtil.getShortName(type)}`;
        }
    }
}