public function setUpRange($elem, $ns = '', $attr = '', $attrNs = '', $datatype = 'string')
    {
        $this->type = 'range';
        $this->elem = (string)$elem;
        $this->ns = (string)$ns;
        $this->attr = (string)$attr;
        $this->attrNs = (string)$attrNs;
        $this->datatype = (string)$datatype;
    }