Powershell Script below Accordion Menu is not Running

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PowerShell

Link:
Dealing with Powershell Inputs via Basic Windows Form[^]

The Scrip is not running i tried all the possible way any one help me to fix the issue the code is run with below Error:
Unable to find type [win32window]: make sure that the assembly containing this
type is loaded.
At line:1 char:34
+ [void]$f.ShowDialog([win32window] <<<< ($caller))
+ CategoryInfo : InvalidOperation: (win32window:String) [], Runti
meException
+ FullyQualifiedErrorId : TypeNotFound


and Kindly let me know how to add that Expand Button to the Lable which showed in the Example