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<?php

add_filter( 'woocommerce_checkout_fields', function ( $fields ) {

    $fields['billing']['billing_country'] = [
        'type'         => 'country',
        'label'        => 'کشور / منطقه',
        'required'     => true,
        'class'        =>
            [
                0 => 'form-row-wide',
                1 => 'address-field',
                2 => 'update_totals_on_change',
            ],
        'autocomplete' => 'country',
        'priority'     => 40,
    ];

    return $fields;
}, 100 );