如何在运营商模型Magento 2中获取自定义字段结帐地址的值

<item name="address" xsi:type="array">
    <item name="component" xsi:type="string">Magento_Checkout/js/view/shipping</item>
    <item name="displayArea" xsi:type="string">billing-address</item>
    <item name="children" xsi:type="array">
        <item name="form-fields" xsi:type="array">
            <item name="custom-field" xsi:type="array">
                <item name="component" xsi:type="string">Magento_Ui/js/form/element/abstract</item>
                <item name="config" xsi:type="array">
                    <item name="customScope" xsi:type="string">billingAddress.custom_attributes</item>
                    <item name="template" xsi:type="string">ui/form/field</item>
                    <item name="elementTmpl" xsi:type="string">ui/form/element/input</item>
                </item>
                <item name="dataScope" xsi:type="string">billingAddress.custom_attributes.custom_field</item>
                <item name="label" xsi:type="string">Custom Field</item>
                <item name="provider" xsi:type="string">checkoutProvider</item>
                <item name="visible" xsi:type="boolean">true</item>
                <item name="sortOrder" xsi:type="string">250</item>
                <item name="validation" xsi:type="array">
                    <item name="required-entry" xsi:type="boolean">false</item>
                </item>
            </item>
        </item>
    </item>
</item>

$address = $quote->getBillingAddress();
$customFieldValue = $address->getCustomField();