type ExtLst = class(OpenXmlElement)
public
    function Create();overload;
    function Create(_node: XmlNode);overload;
    function Create(_parent: tslobj; _prefix: string; _local_name: string);overload;
    function Init();override;
    function Copy(_obj: ExtLst);override;

public

    // multi property
    property Exts read ReadExts;
    function ReadExts(_index);
    function AddExt(): Ext;
    function AppendExt(): Ext;

public
    // Children

end;

function ExtLst.Create();overload;
begin
    {self.}Create(nil, "a", "extLst");
end;

function ExtLst.Create(_node: XmlNode);overload;
begin
    class(OpenXmlElement).Create(_node: XmlNode);
end;

function ExtLst.Create(_parent: tslobj; _prefix: string; _local_name: string);overload;
begin
    setsysparam(pn_calcctrlword(), getsysparam(pn_calcctrlword()) .| 0x200);
    class(OpenXmlElement).Create(_parent, _prefix, _local_name);
end;

function ExtLst.Init();override;
begin
    pre := {self.}Prefix ? {self.}Prefix + ":" : "";
    attributes_ := array();
    attributes_pf_ := array(
    );
    sorted_child_ := array(
        pre + "ext": array(0, makeweakref(thisFunction(AppendExt))),
    );
    container_ := new TSOfficeContainer(sorted_child_);
end;

function ExtLst.Copy(_obj: ExtLst);override;
begin
    tslassigning_backup := tslassigning;
    tslassigning := 1;
    class(OpenXmlElement).Copy(_obj);
    tslassigning := tslassigning_backup;
end;

function ExtLst.ReadExts(_index);
begin
    ind := ifnil(_index) ? -2 : _index;
    pre := {self.}Prefix ? {self.}Prefix + ":" : "";
    return container_.Get(pre + "ext", ind);
end;

function ExtLst.AddExt(): Ext;
begin
    obj := new Ext(self, {self.}Prefix, "ext");
    container_.Insert(obj);
    return obj;
end;

function ExtLst.AppendExt(): Ext;
begin
    obj := new Ext(self, {self.}Prefix, "ext");
    container_.Append(obj);
    return obj;
end;