hangar-wp-plugin/includes/hangar-plugin-init-textdomain.php

<?php
/**
 * Load translation, if it exists
 *
 * This class defines all code necessary to run during the plugin's activation.
 *
 * @link         https://hangar.org
 * @since        1.0.0
 * @package      hangar-wp-plugin
 * @subpackage   hangar-wp-plugin/includes
 * @author       Jorge - vitrubio.net <jorge@vitrubio.net>
 */

function hangar_wpplugin_init_textdomain() {
 load_plugin_textdomain( 'hangar-wpplugin-textdomain', null, plugin_dir_path( __FILE__ ).'/assets/languages/' );
}
add_action('plugins_loaded', 'hangar_wpplugin_init_textdomain');