How to add a Package to Distribution Point Group

$PackageID = 'PR100005'
$DistributionPointGroup = 'New Distribution Group'
$DPGroupQuery = Get-WmiObject -Namespace "Root\SMS\Site_PS1" -Class 'SMS_DistributionPointGroup' -Filter "Name='$DistributionPointGroup'"
$DPGroupQuery.AddPackages($PackageID)