How to mute node with Powershell

I have a script working now to unmanage nodes, however cannot get anything to work to mute them.  Please advise if anyone knows.

Import-Module SwisPowerShell

$swis = Connect-Swis -Credential $mycredentials -Hostname ....

$nodeid = Get-SwisData $swis "SELECT NodeID FROM Orion.Nodes WHERE SysName LIKE'dbprod1a'"

$now =[DateTime]::Now

$later =$now.AddYears(99)

Invoke-SwisVerb $swis Orion.AlertSuppression SuppressAlerts @("N:$nodeid",[DateTime]::UtcNow) | Out-Null