function ParameterDefinitions {
    param(
        [Parameter()][string] $subject = 'punkshell local',
        [Parameter(Mandatory)][string] $friendlyname = 'test code signing',
        [Parameter(ValueFromRemainingArguments)] $opts
    )
}

function psmain {
    [CmdletBinding()]
    param()
    dynamicparam { GetDynamicParamDictionary ParameterDefinitions }
    process {
        #called once with $PSBoundParameters dictionary
        #can be used to validate arguments, or set a simpler variable name for access
        switch ($PSBoundParameters.keys) {
           'subject' { 
               Set-Variable -Name $_ -Value $PSBoundParameters."$_"
           }
           #...
        }
    }
    end {
        Write-Host "Certificate subject is: $subject"
        $params = @{
            Subject = $subject
            Type = 'CodeSigningCert'
            KeySpec = 'Signature'
            KeyUsage = 'DigitalSignature'
            FriendlyName = $friendlyname
            CertStoreLocation = 'Cert:\LocalMachine\My'
            NotAfter = (Get-Date).AddMonths(60)
        }
        Write-Host "please wait..."
        #$cert = New-SelfSignedCertificate @params
        #Write-Host "cert: $cert"

        #echo "Exporting to file for import to certstore.."
        #Export-Certificate -FilePath exported_localmachine_new-cert.cer -Cert $cert
        #Import-Certificate -Filepath exported_localmachine_new-cert.cer -CertstoreLocation Cert:\LocalMachine\My
        #echo "Finished importing.."
           
    }
}

psmain @args