how to export mesh

in the document, i found there are some options about exporting mesh, but i didnt find it in Sampler...

thus, i try to achieve it through python API. but an error occurred after running it：

”Cannot call export_mesh on anything but a 3D object

导出文件夹路径：“ 

i wonder is there a method can select the 3d model? the method "get_selected_asset()" only gets the material type.

(run "asset = substance_sampler.get_selected_asset()

        print (asset.type)"

return Assettype.material)

my code below:

import substance_sampler

# 创建 Asset 对象
asset = substance_sampler.get_selected_asset()

# 设置导出参数
export_path = "C:/Users/maxiqq/Desktop"
export_name = "exported_object"

# 调用 export_3d_object() 函数导出 3D 物体
export_folder_path = asset.export_mesh(path=export_path, name=export_name, format = substance_sampler.MeshExportFormat.obj)

# 打印导出文件夹路径
print("导出文件夹路径：", export_folder_path)