How do I make batch callbacks as class methods?
When I use a callback function what live in a class I use, for example:

'finished' =&gt; array('\Drupal\my_batch\Form\MyBatchForm', 'finish_function'),


The same with 'operations':

'operations' =&gt; array(array('\Drupal\my_batch\Form\MyBatchForm', 'operation_function'), array($node-&gt;id())),