Taken from the Codex and Dev Hubs:
<?php get_template_part( $slug ); ?> <?php get_template_part( $slug, $name ); ?>
get_template_part only takes 2 parameters, not 3. If you look in your error log you should be seeing warnings and notices that you passed a third parameter to a function that only takes 2. I would expect your call to load the file content-page.php then content.php. Nothing is done with kahvilaravintola, as it’s an unexpected and unused third parameter