Require a minimum order total in Woocommerce for a user role

functions.php

<?php

/*
Author: Doug Edgington
Description: Require a minimum order total in Woocommerce for a user role
*/

function dee_minimum_order_total_required() {
	if( is_user_logged_in() ) { 

		global $woocommerce;
		global $current_user;
		
		get_currentuserinfo();
		
		$dee_user_roles = $current_user->roles;
		$dee_user_role = array_shift($dee_user_roles);
		
		$dee_minimum = 50;
		if ( $woocommerce->cart->subtotal < $dee_minimum  && $dee_user_role == 'wholesale_buyer') {
			$woocommerce->add_error( sprintf( 'Wholesale users must have a minimum order total of $%s to place an order.' , $dee_minimum ) );
		}
	} //end main if statement
}
add_action( 'woocommerce_checkout_process', 'dee_minimum_order_total_required' );

?>

Hi, i tried to put that shortcode on my functions.php but nothing changes.. i also changed 'wholesale_buyer' with my 'wholesale_customer'.. can you help me ? thank you, Luca