How to check if a XSLT transformation with powerShell has finished?

Question

I'm using windows powershell for XSLT transformations. This my example:

$aTransformation= New-Object System.Xml.Xsl.XslCompiledTransform;
$aTransformation.load( "transformation.xslt" )
$aTransformation.Transform( "input.xml", "output.html" )

Is there any posibility to check when the transformation has finished? .Transform seems to be only a void method. Target is to use a script for several transformations.