Pagination Error

I’m having a problem with the pagination function for my page.

I have this error: Warning: Missing argument 2 for add_action(), called in /data/web/virtuals/135410/virtual/www/wp-content/themes/baskerville-child/functions.php on line 19 and defined in /data/web/virtuals/135410/virtual/www/wp-includes/plugin.php on line 457

Here’s the code that I am currently using in functions.php

add_action( 'wpex_pagination' );

if ( !function_exists( 'wpex_pagination' ) ) {

	function wpex_pagination() {

		$prev_arrow = is_rtl() ? '→' : '←';
		$next_arrow = is_rtl() ? '←' : '→';

		global $wp_query;
		$total = $wp_query->max_num_pages;
		$big = 999999999; // need an unlikely integer
		if( $total > 1 )  {
			 if( !$current_page = get_query_var('paged') )
				 $current_page = 1;
			 if( get_option('permalink_structure') ) {
				 $format = 'page/%#%/';
			 } else {
				 $format = '&paged=%#%';
			 }
			echo paginate_links(array(
				'base'			=> str_replace( $big, '%#%', esc_url( get_pagenum_link( $big ) ) ),
				'format'		=> $format,
				'current'		=> max( 1, get_query_var('paged') ),
				'total' 		=> $total,
				'mid_size'		=> 1,
				'type' 			=> 'list',
				'prev_text'		=> $prev_arrow,
				'next_text'		=> $next_arrow,
			 ) );
		}
	}

}

Any help would be greatly appreciated. Thanks.