Powershell: Does a value exist in the registry

param
(
        [Parameter(Mandatory=$True)]
        [string]$subkeyname,
        [Parameter(Mandatory=$True)]
        [string]$ValueName,
)

$regkey = [Microsoft.Win32.Registry]::ClassesRoot
$value = $regkey.OpenSubKey($subkeyname).GetValue($ValueName)
if(!($value))
{
    write-host "Value does not exist."
}
else
{
    write-host "Value exists."
}