PHP在foreach之后返回NULL数组

我不知道为什么我的函数总是返回NULL。return之前的var_dump($args)显示了$args中的过多项。但是当我在另一个地方调用这个函数时，它返回NULL。有人能帮帮我吗?谢谢。

在备忘录中我解释了情况。

function LBE_result_hompage_search_ecole_map()
{
    //  Get department code when user click map
    $code = $_POST['code'];
    // Query data from database
    global $wpdb;
    $table_name = $wpdb->prefix.'utils_ville';
    $query = "SELECT nom_ville,code_postal FROM ".$table_name." WHERE departement=%d";
    $results = $wpdb->get_results( $wpdb->prepare($query, $code) );
    $args = array();
    foreach($results as $result):
        $arg = array(
            'posts_per_page'   => 10,
            'orderby'          => 'post_date',
            'order'            => 'DESC',
            'post_type'        => 'ecole',
            'post_status'      => 'publish',
            'meta_query'       => array(
            'relation' => 'AND',
                array(
                    'key' => 'ecole_ville',
                    'value' => $result->nom_ville,
                    'compare' => '='
                ),
                array(
                    'key' => 'ecole_post',
                    'value' => $result->code_postal,
                    'compare' => '='
                )
            )
        );
        $args[] = $arg;
    endforeach;
    var_dump($args);  // Here shows so many items in $args
    return($agrs);
}
$args = LBE_result_hompage_search_ecole_map();
var_dump($args);  // Here shows NULL. I don't know why...