Adding Template Parts with Shortcode

functions.php

<?php
// Add a shorcode to get the template part
function makeagency_shortcode() {
    ob_start();
    get_template_part('templates/this', 'template');
    return ob_get_clean();   
} 
add_shortcode( 'tax_calculator', 'makeagency_shortcode' );

// Check the post for the shortcode and enque the scripts
function makeagency_shortcode_scripts() {
	global $post;
	if( is_a( $post, 'WP_Post' ) && has_shortcode( $post->post_content, 'makeagency_shortcode') ) {
		wp_enqueue_style(  'shortcode_styles', get_template_directory_uri() . '/css/shortcode.css', array(), '1.0.0', 'all' );
		wp_enqueue_script(  'shortcode_js', get_template_directory_uri() . '/js/shortcode.js', array(), '1.0.0', 'all' );
	}
}
add_action( 'wp_enqueue_scripts', 'makeagency_shortcode_scripts');