Private/Start-CustomVMUpdate.ps1

# Will be called in VM
function Global:Start-CustomVMUpdate {
    [CmdletBinding()]
    <#
    .SYNOPSIS
        ...
    .DESCRIPTION
        ...
    #>

    param(
        [Parameter(Mandatory = $true, Position = 1)]
        [string]
        $ObjectName,
        [Parameter(Mandatory = $false, Position = 2)]
        [switch]
        $IsScaleSet,
        [Parameter(Mandatory = $true, Position = 3)]
        [string]
        $ResourceGroupName,
        [Parameter(Mandatory = $true, Position = 4)]
        [string]
        $StorageAccountName
    )
    process {
        Write-Host "Starting auto update..."
    }
}