How to use the @ptsecurity/mosaic/tree.McTreeFlatDataSource function in @ptsecurity/mosaic

constructor(database: FileDatabase) {
        this.treeFlattener = new McTreeFlattener(
            this.transformer, this._getLevel, this._isExpandable, this._getChildren
        );

        this.treeControl = new FlatTreeControl(this._getLevel, this._isExpandable);
        this.dataSource = new McTreeFlatDataSource(this.treeControl, this.treeFlattener);

        this.nestedTreeControl = new NestedTreeControl(this._getChildren);
        this.nestedDataSource = new McTreeNestedDataSource();

        database.dataChange.subscribe((data) => {
            this.dataSource.data = data;
            this.nestedDataSource.data = data;
        });
    }

constructor() {
        this.treeFlattener = new McTreeFlattener(
            this.transformer, this.getLevel, this.isExpandable, this.getChildren
        );

        this.treeControl = new FlatTreeControl(
            this.getLevel, this.isExpandable, this.getValue, this.getViewValue
        );
        this.dataSource = new McTreeFlatDataSource(this.treeControl, this.treeFlattener);

        this.dataSource.data = buildFileTree(DATA_OBJECT, 0);
    }

constructor() {
        this.treeFlattener = new McTreeFlattener(
            this.transformer, this.getLevel, this.isExpandable, this.getChildren
        );

        this.treeControl = new FlatTreeControl(
            this.getLevel, this.isExpandable, this.getValue, this.getViewValue
        );
        this.dataSource = new McTreeFlatDataSource(this.treeControl, this.treeFlattener);

        this.dataSource.data = buildFileTree(DATA_OBJECT, 0);
    }

constructor() {
        this.treeFlattener = new McTreeFlattener(
            this.transformer, this.getLevel, this.isExpandable, this.getChildren
        );

        this.treeControl = new FlatTreeControl(
            this.getLevel, this.isExpandable, this.getValue, this.getViewValue
        );
        this.dataSource = new McTreeFlatDataSource(this.treeControl, this.treeFlattener);

        this.dataSource.data = buildFileTree(DATA_OBJECT, 0);
    }

constructor() {
        this.treeFlattener = new McTreeFlattener(
            this.transformer, this.getLevel, this.isExpandable, this.getChildren
        );

        this.treeControl = new FlatTreeControl(
            this.getLevel, this.isExpandable, this.getValue, this.getViewValue
        );
        this.dataSource = new McTreeFlatDataSource(this.treeControl, this.treeFlattener);

        this.dataSource.data = buildFileTree(DATA_OBJECT, 0);
    }

constructor() {
        this.treeFlattener = new McTreeFlattener(
            this.transformer, this.getLevel, this.isExpandable, this.getChildren
        );

        this.treeControl = new FlatTreeControl(
            this.getLevel, this.isExpandable, this.getValue, this.getViewValue
        );
        this.dataSource = new McTreeFlatDataSource(this.treeControl, this.treeFlattener);

        this.dataSource.data = buildFileTree(DATA_OBJECT, 0);
    }

constructor() {
        this.treeFlattener = new McTreeFlattener(
            this.transformer, this.getLevel, this.isExpandable, this.getChildren
        );

        this.treeControl = new FlatTreeControl(
            this.getLevel, this.isExpandable, this.getValue, this.getViewValue
        );
        this.dataSource = new McTreeFlatDataSource(this.treeControl, this.treeFlattener);

        this.dataSource.data = buildFileTree(DATA_OBJECT, 0);
    }

constructor(private modalService: McModalService) {
        setInterval(() => {
            this.percent = (this.percent + STEP) % (MAX_PERCENT + STEP);
        }, INTERVAL);

        this.treeFlattener = new McTreeFlattener(
            this.transformer, this.getLevel, this.isExpandable, this.getChildren
        );

        this.treeControl = new FlatTreeControl(
            this.getLevel, this.isExpandable, this.getValue, this.getViewValue
        );

        this.dataSource = new McTreeFlatDataSource(this.treeControl, this.treeFlattener);

        this.dataSource.data = buildFileTree(DATA_OBJECT, 0);
    }

constructor() {
        this.treeFlattener = new McTreeFlattener(
            this.transformer, this.getLevel, this.isExpandable, this.getChildren
        );

        this.treeControl = new FlatTreeControl(
            this.getLevel, this.isExpandable, this.getValue, this.getViewValue
        );
        this.dataSource = new McTreeFlatDataSource(this.treeControl, this.treeFlattener);

        this.dataSource.data = buildFileTree(DATA_OBJECT, 0);
    }