Class parameters for get_preview?

Hello,

Would it be possible to add a class parameter to get_preview function found in TimberPost?

I need to add some classes and use http://twig.sensiolabs.org/doc/filters/replace.html now to replace “read-more” with “read-more btn”

Would be nice if it could be done with a parameter.

https://ww.wp.xz.cn/plugins/timber-library/