How to set password to laravel envoy script?

Hello, In laravel 5.8 I running envoy I want to set password of user in console command, like

envoy run Deploy  --serveruser_password=mypass1112233
Having in envoy file: 
@setup
    $server_login_user= 'serveruser';
    $user_password = isset($serveruser_password) ? $serveruser_password : "Not Defined";

@endsetup

@task( 'clone_project', ['on'=>$on] )
    echo '$user_password password ::';
    echo $user_password;

But $user_password output empty in both cases :

1. if serveruser_password is set in command

envoy run Deploy  --serveruser_password=mypass1112233

1. or it is empty

envoy run Deploy

But I expected "Not Defined" outputed...

Why error and how coreect ?

Thanks!