code: public String write(Map<String, String> outputProperties) {
  		StringWriter sw = new StringWriter();
  		try {
  			write(sw, outputProperties);
  		} catch (TransformerException e) {
  			//shouldn't be thrown because we're writing to a string
  			throw new RuntimeException(e);
  		}
  		return sw.toString();
  	}
docs: Writes the xCal document to a string.
  @param outputProperties properties to assign to the JAXP transformer (see
  {@link Transformer#setOutputProperty})
  @return the XML string