GetListSample.php

<?php

namespace My\Custom\Namespace;

class MyAdmin extends ModelAdmin
{
  private static $managed_models = [
    'myModelKey' => [
      'dataClass' => MyClass::class,
      'title' => 'My Class Title',
    ],
    'myOtherModelKey' => [
      'dataClass' => MyOtherClass::class,
      'title' => 'My Other Class Title',
    ],
  ];
  
  /**
     * @return DataList
     */
    public function getList()
    {
        $list = parent::getList();

        if ($this->modelTab === 'myModelKey') {
            $list = $list->filter([
                'ClassName' => MyClass::class,
            ]);
        }

        return $list;
    }
}