Post navigation change tekst

Hi support,
Is it possible to change the Next and Previous links beneath a post to actually the text Next post / Previous post? Now I see the title of the post.
I tried following code for functions.php (I have child theme) I found with Google but not working:

//
add_filter( 'tc_singular_nav_next_text' , 'my_nav_buttons_text' );
add_filter( 'tc_singular_nav_previous_text' , 'my_nav_buttons_text' );
 
function my_nav_buttons_text() {
  switch ( current_filter() ) {
    case 'tc_singular_nav_previous_text':
      return 'previous post &larr;'; // <= your custom text here
    case 'tc_singular_nav_next_text':
      return '&rarr; next post'; // <= your custom text here
  }
}

Thanks!