How do I validate if a XML tag missing < or /> using powershell

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PowerShell

Team, please help me how can I validate following xml format using PowerShell. See the forth line don't have "<".

<AccountValue>
	<IsNumeric>false</IsNumeric>
	<Length>1,2,3,4,5</Length>
	StartChars/>
	<TrailChars/>
	<Expression>^[0-9]+$</Expression>
</AccountValue>

suppose I save the above content in c:\temp\test.xml. And when I run following code it did not show any error.

$xmlfile = c:\temp\test.xml
$xml = New-Object System.Xml.XmlDocument
$xml.Load($xmlfile)

My question is how can I produce the error without xsd.

xml.Load($xmlfile)

should produce error.

What I have tried:

I tried XmlDocument.Load Method but it did not show any error.