private/dev/Get-MyDeviceModel.ps1

function Get-MyDeviceModel {
    [CmdletBinding()]
    param ()
    $deviceManufacturer = Get-MyDeviceManufacturer
    if ($deviceManufacturer -match 'Lenovo') {
        $deviceModel = ((Get-CimInstance -ClassName Win32_ComputerSystemProduct).Version).Trim()
    }
    else {
        $deviceModel = ((Get-CimInstance -ClassName CIM_ComputerSystem).Model).Trim()
    }
    $deviceModel = $deviceModel -as [string]
    if ([string]::IsNullOrWhiteSpace($deviceModel)) {
        $deviceModel = 'OEM'
    } elseif ($deviceModel -match 'OEM|to be filled') {
        $deviceModel = 'OEM'
    }
    return $deviceModel
}