Add Expiration/Rentention policy in Sharepoint Through powershell

Below is the power-shell script which can be used to add expiration/Retention policy in any version of share-point  through powershell.This helps in moving the policy from one environment to other in a very easy and hassle free way.
               Below power shell script adds the expiration policy to the Content Type at the site collection level ,This is designed to add at Site collection level because this can be run in the Content Hub hosting site and the policy can be migrated to other site collections which are leveraging the Hub.You can make the necessary changes to the script to add the policy at the "Library level" or" to the "content type " at the library level by instantiating the suitable object .
      The script below add the expiration policy like "DocumentDate+0 days" move to "Recycle bin"
"DocumentDate" is my custom column of DateTime type field.



$snapin = Get-PSSnapin | Where-Object {$_.Name -eq 'Microsoft.SharePoint.Powershell'}
if ($snapin -eq $null) {
Write-Host "Loading SharePoint Powershell Snapin"
Add-PSSnapin "Microsoft.SharePoint.Powershell"
}
$logFile = "LogFile_RDM_Expiration_Policy"

function AddExpirationPolicy($web , $contentTypes)
 {
     try
     {
        $arrayCT = $contentTypes.Split(",")
        foreach($CT in $arrayCT)
         {
              Write-host -for yellow "Checking if the Content type" $CT "exists ?"
              Add-Content $logFile "Checking if the Content type $CT exists ?"
              $CT = $web.ContentTypes[$CT]
              if($CT -ne $null)
              {
                Write-host -ForegroundColor green "Content Types -" $CT.Name  "exists !!"
                Add-Content $logFile "Content Types - $CT.Name exists !!"
                $policy=[Microsoft.Office.RecordsManagement.InformationPolicy.Policy]::GetPolicy($CT);
                 if ($policy -eq $null)
                   {
                    $policy=[Microsoft.Office.RecordsManagement.InformationPolicy.Policy]:: CreatePolicy($CT,$null);
                    $policy=[Microsoft.Office.RecordsManagement.InformationPolicy.Policy]::GetPolicy($CT);
                   }
                $policy.Description="Thilosh expiration Policy";
                $policy.Statement="Thilosh expiration Policy";
                $policy.Update();
                $expirypolicyexists=$false;
                if ($policy.Items.Count -ne 0)
                {
                foreach ($policyitem in $policy.Items)
                {
                    if ($policyitem.Name -eq "Retention")
                    {
                        $expirypolicyexists=$true;
                    }
                }
                }
                if ($expirypolicyexists -eq $false)
                 {
                $policyFeatureID = [Microsoft.Office.RecordsManagement.PolicyFeatures.Expiration];
                #Expires data when the current date is equal to the document date set for the record      
                $customData = '<Schedules nextStageId="2">
                                <Schedule type="Default">
                                <stages>
                                  <data stageId="1">
                                    <formula id="Microsoft.Office.RecordsManagement.PolicyFeatures.Expiration.Formula.BuiltIn">
                                      <number>0</number>
                                      <property>DocumentDate</property>                        
                                      <period>days</period>
                                    </formula>
                                    <action type="action" id="Microsoft.Office.RecordsManagement.PolicyFeatures.Expiration.Action.MoveToRecycleBin" />
                                  </data>
                                </stages>
                              </Schedule>
                            </Schedules>'
                $policy.Items.Add($policyFeatureID,$customData);
                #$policy.Items.Add("Microsoft.Office.RecordsManagement.PolicyFeatures.Expiration",$customData);
                $policy.Update();
                Write-Host -ForegroundColor Green  "Expiration  policy added for thr Content Type -" $CT.Name
                Add-Content $logFile "Expiration  policy added for thr Content Type - $CT.Name"
                 }
                else
                 {
                   Write-Host -ForegroundColor Red  "An expiry policy already exists and is not overwritten for the Content type -" $CT.Name
                   Add-Content $logFile   "An expiry policy already exists and is not overwritten for the Content type - $CT.Name"
                 }
              }
              else
              {
                Write-host -ForegroundColor red "Content Types -" $CT  "doesnot exists !!"
                Add-Content $logFile "Content Types - $CT doesnot exists !!"
              }
         
       }
     }
     catch
     {
         Write-Host  $_.Exception.Message      
         Add-Content $logFile    "***Error description Starts****`n"
         Add-Content $logFile    $_.Exception.Message        
         Add-Content $logFile    "***Error description ends****`n"

     }
 }

 $siteURL = Read-Host "Enter the Site collection URL - Eg:http://Thilosh:1234/ "
 $site = Get-SPSite -Identity  $siteURL
 $web = $site.RootWeb
 $contentTypes =  "ContentType1,ContentType2,ContentType3"

 AddExpirationPolicy $web $contentTypes

 $web.Dispose();
 $site.Dispose();




Read-Host "Press enter Key to exit !!"



Now you must be thinking how do I change the formula in "$customData ".This is very simple,You must have heard about a tool named "Sharepoint Manager" by using this you should be able to create formula for literally anything what ever possible in the sharepoint :)