POSH update XPath with specified value

edit-xmlnodes.ps1

# Inputs
param (
    [string] $doc = $(throw "doc is a required parameter"),
    [string] $xpath = $(throw "xpath is a required parameter"),
    [string] $value = $(throw "value is a required parameter")
)

function Edit-XmlNodes {
    # Open the file
    $filepath = Resolve-Path $doc
    $xml = [xml](Get-Content $filepath)
    # Find the nodes to modify
    $nodes = $xml.SelectNodes($xpath)
    # Set value of discovered nodes
    foreach ($node in $nodes) {
        write-host $node.OuterXml
        if ($node -ne $null) {
            if ($node.NodeType -eq "Element") {
                $node.InnerXml = $value
            }
            else {
                $node.Value = $value
            }
        }
        write-host $node.OuterXml
    }
    # Save result
    $xml.Save($filepath)
}

Edit-XmlNodes -doc $doc -xpath $xpath -value $value