azurerm_virtual_machine_data_disk_attachment is not getting required parameter in aztfexport.

resource "azurerm_virtual_machine_data_disk_attachment" "res-3" {
caching = "None"
managed_disk_id = "/subscriptions/XXX/resourceGroups/RG/providers/Microsoft.Compute/disks/testvm_DataDisk_0"
virtual_machine_id = "/subscriptions/XXX/resourceGroups/RG/providers/Microsoft.Compute/virtualMachines/TestVMBackupRG"
depends_on = [
azurerm_managed_disk.res-1,
azurerm_linux_virtual_machine.res-2,
]

it gives error when i run terraform plan

│ Error: Missing required argument
│
│ on main.tf line 46, in resource "azurerm_virtual_machine_data_disk_attachment" "res-3":
│ 46: resource "azurerm_virtual_machine_data_disk_attachment" "res-3" {
│
│ The argument "lun" is required, but no definition was found.