}
Element addTaxonomy(final Element rootElement, final MixTaxonomyData taxonomy, final BigDecimal value) {
// throw an error is start / endate is null
if (this.startDate == null || this.endDate == null) { throw new XBRLMappingInvalidException(
"start date and end date should not be null"); }
final String prefix = taxonomy.getNamespace();
String qname = taxonomy.getName();
if (prefix != null && (!prefix.isEmpty())) {