Для чего примеры на php в документации?

PHP

public static function Execute($instance, $project)
{
    // clear cookie
    $instance->ClearCookie();
   
    // go to lessons.zennolab.com
    $tab = $instance->MainTab;
    if (($tab->IsVoid) || ($tab->IsNull)) return -1;
    if ($tab->IsBusy) $tab->WaitDownloading();
    $tab->Navigate("lessons.zennolab.com");
    if ($tab->IsBusy) $tab->WaitDownloading();
   
    // find elements by tag
    $heCol = $tab->FindElementsByTags("input:checkbox");
   
    // if any element was not found
    if ($heCol->Count == 0) return -1;
   
    // get last element by index (number)
    $he = $heCol->GetByNumber($heCol->Count-1);
   
    return 0;
}