Wordpress Activate plugin programatically

function run_activate_plugin( $plugin ) {
    $current = get_option( 'active_plugins' );
    $plugin = plugin_basename( trim( $plugin ) );

    if ( !in_array( $plugin, $current ) ) {
        $current[] = $plugin;
        sort( $current );
        do_action( 'activate_plugin', trim( $plugin ) );
        update_option( 'active_plugins', $current );
        do_action( 'activate_' . trim( $plugin ) );
        do_action( 'activated_plugin', trim( $plugin) );
    }

    return null;
}
run_activate_plugin( 'plugin_dir/plugin_file.php' );