Adding custom more link to template tags in TB-Testimonials

foo.php

<?php

    add_action( 'tbt_template_functions', 'add_tags_to_tbt' );

    /**
    * add custom template tags to tbtestimonials plugin
    *
    * @param mixed $t - twig instance
    */
    function add_tags_to_tbt( $t )
    {
        $t->addGlobal( 'page_link', call_user_func( 'tbt_testimonial_page_link' ) );
    }

    /**
    * return link to testimonials page
    *
    */
    function tbt_testimonial_page_link()
    {
        if( $page = get_page_by_title( 'testimonials' ) ){
            return sprintf( ' <a href="%s#testimonial-%d">Read More</a>', get_permalink( $page->ID ), get_the_ID() );
        }
        return false;
    }