Filter to determine if an item derives from a particular template

IsOfTemplateFilter.ps1

Function Where-TemplateDerives {
    param(
        [Parameter(Mandatory=$true,ValueFromPipeline=$true)]
        [Sitecore.Data.Items.Item]$Item,
        
        [Parameter(Mandatory=$true,Position=0)]
        [string]$TemplateID
    )
    
    process {
        if ($Item) {
            $template = [Sitecore.Data.Managers.TemplateManager]::GetTemplate($Item)
    
            if ($template.DescendsFromOrEquals($TemplateID)) {
                $Item
            }
        }
    }
}