code: function doExport() {
  		/*
  			If opts is array of arrays then this is a
  			multisheet workboook, else it is a singlesheet
  		*/
  		if (typeof opts == 'object' && Array.isArray(opts)) {
  			if (data && data.length > 0) {
  				data.forEach(function(dat, idx) {
  					prepareSheet(opts[idx], dat, undefined, idx + 1);
  				});
  			}
  		} else {
  			prepareSheet(opts, data, columns, 1);
  		}
  
  		saveWorkbook(cb);
  	}
docs: Export workbook
  @function