Detach unused RDMs from ESXi Cluster

Hi,

I am issues detaching unused RDMs from ESXi Cluster.

I am using below script and getting error

Connect-viserver 10.10.10.10

$lun = "naa.60a98000424c7841583f4a596b73556e"

Get-Cluster -Name My-Compute | Get-VMHost | %{Detach-Disk -VMHost $_ -CanonicalName $lun}

Error

Detach-Disk : The term 'Detach-Disk' is not recognized as the name of a cmdlet, function, script file, or operable program. Check the spelling of the name, or if a path was

included, verify that the path is correct and try again.

At D:\detach.ps1:3 char:47

+ Get-Cluster -Name My-Compute | Get-VMHost | %{Detach-Disk -VMHost $_ -CanonicalN ...

+                                               ~~~~~~~~~~~

    + CategoryInfo          : ObjectNotFound: (Detach-Disk:String) [], CommandNotFoundException

    + FullyQualifiedErrorId : CommandNotFoundException

Please help...