XML : R save nested data.table to xml

I have nested data.table, namely:

  Table <- data.table(COLUMN1 = 'ABC', COLUMN2 = 1)  Table[, NESTED_TABLE := list(list(data.table(COL1 = c(1,2), COL2 = c(3,4))))]    

I want to save nested data.table to xml. By now, I found out function which convert data.frame / list to xml, but for nested element it returns null in xml file. How can I modify function to have nested data.table structure in XML?

  objectToXML <- function(item, tag){      if("data.frame" %in% class(item)) {      nodeList <- list()        if(nrow(item) > 0) {          for(i in 1:nrow(item)) {          newNode <- xmlNode(tag)            irow <- item[i,]            for(name in names(irow)) {            newNode <- append.xmlNode(newNode, xmlNode(name, irow[[name]]))          }            nodeList[[i]] <- newNode        }      }        return(nodeList)    }      if(typeof(item)!='list')      return(xmlNode(tag, item))      xml <- xmlNode(tag)      for(name in names(item)){      xml <- append.xmlNode(xml, objectToXML(item[[name]], name))    }      return(xml)  }