我已获得此代码，但无法通过billing\\u phone进行搜索

<form role="search" method="get" id="searchform" class="searchform" action="<?php echo site_url(\'/\'); ?>">
    <div class="user-form">
        <label class="screen-reader-text" for="s">Search for:</label>
        <input type="text" value="<?php echo get_search_query(); ?>" name="s" id="s" />
        <input type="submit" id="searchsubmit" value="Search" />
    </div>
</form> .author-search -->

<?php
if( $_GET[\'s\'] ) {

    $search_term = sanitize_text_field( stripslashes( $_GET[\'s\']));


// WP_User_Query arguments
$args = array (
    \'role\'       => \'Customer\',
    \'order\'      => \'ASC\',
    \'orderby\'    => \'display_name\',
    \'search\' => \'*\' . esc_attr( $search_term ) . \'*\',
    \'meta_query\' => array(
        \'relation\' => \'OR\',
        array(
            \'key\'     => \'nickname\',
            \'value\'   => $search_term,
            \'compare\' => \'LIKE\'
        ),
        array(
            \'key\'     => \'last_name\',
            \'value\'   => $search_term,
            \'compare\' => \'LIKE\'
        ),
        array(
            \'key\'     => \'billing_phone\',
            \'value\'   => $search_term,
            \'compare\' => \'LIKE\'
        )
    )
);

// Create the WP_User_Query object
$wp_user_query = new WP_User_Query( $args );

// Get the results
$authors = $wp_user_query->get_results();

// Check for results
if ( ! empty( $authors ) ) {
    echo \'<ul>\';
    // loop through each author
    foreach ( $authors as $author ) {
        // get all the user\'s data
        $author_info = get_userdata( $author->ID );
        echo \'<li>\' . $author_info->nickname . \' \' . $author_info->last_name . \'</li>\';
                echo \'<li>\' . $author_info->billing_phone . \'</li><br>\';

    }
    echo \'</ul>\';
} 

else {
    echo \'No authors found\';
}

}
?>