How to call plugin function in namespace?

Hi,

To prevent name collision, I want to use namespace instead of adding prefix to each function:

Below is my code:

<?php

/*
 * Plugin Name: My Test Plugin
 */


namespace dnip_add_image_links;

if (!defined('ABSPATH')) 
	exit; // Exit if accessed directly

add_action('admin_post_dnip_add_image_links', 'dnip_add_image_links');
add_action('admin_post_nopriv_dnip_add_image_links', 'dnip_add_image_links');

function dnip_add_image_links() 
{
}

But when calling with the following URL:

http://127.0.0.2/wp-admin/admin-post.php?action=dnip_add_image_links&nocache=123

I get the following error:

Fatal error: Uncaught TypeError: call_user_func_array(): Argument #1 ($callback) must be a valid callback, function "dnip_add_image_links" not found or invalid function name in C:\wamp64\www\blogs\wp-includes\class-wp-hook.php:324 Stack trace: #0 C:\wamp64\www\blogs\wp-includes\class-wp-hook.php(348): WP_Hook->apply_filters('', Array) #1 C:\wamp64\www\blogs\wp-includes\plugin.php(517): WP_Hook->do_action(Array) #2 C:\wamp64\www\blogs\wp-admin\admin-post.php(85): do_action('admin_post_dnip...') #3 {main} thrown in C:\wamp64\www\blogs\wp-includes\class-wp-hook.php on line 324
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So, how to implement the plugin in the namespace?