Can session autoload?

Unfortunately what loved a Codeigniter earlier now for was lost - documentation very bad
I create new project on CI 4
How i can autoload session
app/Config/Autoload.php

Code:

$psr4 = [
            'Config'      => APPPATH . 'Config',
            APP_NAMESPACE => APPPATH,                // For custom namespace
            'App'         => APPPATH,                // To ensure filters, etc still found,
            'Session'     => SYSPATH . 'Session',
            
        ];

Result - Warning: Use of undefined constant SYSPATH - assumed 'SYSPATH' (this will throw an Error in a future version of PHP)
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