btn-primary is not always welcome for submit

I use symfony's crud generator. It generates separate delete form. So the problem is that it submit button has <code>btn-primary</code> class. Even when I put <code>btn-danger</code> class as attribute in form creation, the button has both <code>btn-primary</code> and <code>btn-danger</code> classes. And unfortunately primary class is accepted. It comes from <a href="https://github.com/braincrafted/bootstrap-bundle/blob/develop/Resources/views/Form/bootstrap.html.twig#L480">here</a>. Should I just override it? Or there is more elegant solution?