Query : What is the use of "Empty" in create_option parameter of data disk attachment

Hi Team,

Can you please let us know what is the use of “Empty” value in create_option parameter of azurerm_virtual_machine_data_disk_attachment resource, as this would be very much useful to us for performing data disk attachment.
We tried with “Attach” option and the disk is getting attached successfully, but we are curious to know what is the use of “Empty” value in create_option parameter.

Please find the link that we are referring to for data disk attachment:
https://registry.terraform.io/providers/hashicorp/azurerm/2.63.0/docs/resources/virtual_machine_data_disk_attachment

Thanks