public/Get-VSASD.ps1

function Get-VSASD {
    <#
    .Synopsis
       Returns an array of service desk definitions.
    .DESCRIPTION
       Returns an array of service desk definitions.
       Takes either persistent or non-persistent connection information.
    .PARAMETER VSAConnection
        Specifies existing non-persistent VSAConnection.
    .PARAMETER URISuffix
        Specifies URI suffix if it differs from the default.
    .PARAMETER Filter
        Specifies REST API Filter.
    .PARAMETER Paging
        Specifies REST API Paging.
    .PARAMETER Sort
        Specifies REST API Sorting.
    .EXAMPLE
       Get-VSASD
    .EXAMPLE
       Get-VSASD -VSAConnection $connection
    .INPUTS
       Accepts piped non-persistent VSAConnection
    .OUTPUTS
       Array of items that represent service desks and their properties
    #>


    [CmdletBinding()]
    param ( 
        [parameter(Mandatory = $true, 
            ValueFromPipelineByPropertyName = $true,
            ParameterSetName = 'NonPersistent')]
        [VSAConnection] $VSAConnection,
        [parameter(Mandatory=$false,
            ValueFromPipelineByPropertyName=$true,
            ParameterSetName = 'NonPersistent')]
        [parameter(Mandatory=$false,
            ValueFromPipelineByPropertyName=$true,
            ParameterSetName = 'Persistent')]
        [ValidateNotNullOrEmpty()] 
        [string] $URISuffix = 'api/v1.0/automation/servicedesks',
        [Parameter(ParameterSetName = 'Persistent', Mandatory = $false)]
        [Parameter(ParameterSetName = 'NonPersistent', Mandatory = $false)]
        [ValidateNotNullOrEmpty()] 
        [string] $Filter,
        [Parameter(ParameterSetName = 'Persistent', Mandatory = $false)]
        [Parameter(ParameterSetName = 'NonPersistent', Mandatory = $false)]
        [ValidateNotNullOrEmpty()] 
        [string] $Paging,
        [Parameter(ParameterSetName = 'Persistent', Mandatory = $false)]
        [Parameter(ParameterSetName = 'NonPersistent', Mandatory = $false)]
        [ValidateNotNullOrEmpty()] 
        [string] $Sort
    )

    [hashtable]$Params =@{
        URISuffix = $URISuffix
    }

    if($VSAConnection) {$Params.Add('VSAConnection', $VSAConnection)}
    if($Filter)        {$Params.Add('Filter', $Filter)}
    if($Paging)        {$Params.Add('Paging', $Paging)}
    if($Sort)          {$Params.Add('Sort', $Sort)}

    return Get-VSAItems @Params
}

Export-ModuleMember -Function Get-VSASD