PowerShell - Get certificate Information from text list of servers

This saved as a .ps1. grabs machines from c:\temp\servers.txt and collects the x509 certificate information for each server, Outputs to c:\temp\CertificatesFromListedServers.csv

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$a = Get-Content C:\temp\servers.txt

Invoke-Command -ComputerName $a -Scriptblock{

Get-ChildItem Cert:\LocalMachine\root | Where-Object {$_ -is [System.Security.Cryptography.X509Certificates.X509Certificate2] -and $_.NotAfter -lt (Get-Date)} | Select-Object -Property PSComputerName,FriendlyName,Subject,NotBefore,NotAfter,Issuer,Thumbprint

} | Export-Csv c:\temp\CertificatesFromListedServers.csv

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