file exist in WordPress upload Folder

functions.php

<?php
global $product;
    $upload_dir = wp_upload_dir();
    $file_location = $upload_dir['basedir'].'/'."acf_attached_file".'/'.$product->get_slug().'.pdf';

if(file_exists($file_location)) {
 echo "file exist"; 
}
else {
 echo "not exist"; 
}

//or

if(file_exists($file_location)) :
 echo "file exist"; 
else :
 echo "not exist"; 
endif;