code: public void write(Writer writer, Integer indent) throws TransformerException {
  		write(writer, indent, null);
  	}
docs: Writes the xCal document to a writer.
  @param writer the writer
  @param indent the number of indent spaces to use for pretty-printing or
  "null" to disable pretty-printing (disabled by default)
  @throws TransformerException if there's a problem writing to the writer